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Ratios, Relationships, and the Number System

Grade 6 · Christian · NGSS/CCSS-aligned

This is the year your child learns to think in ratios instead of just counting differences — "for every 3 of these, 2 of those" instead of "3 more of these." That one idea (a multiplicative relationship between two quantities) gets used all year: to divide fractions, to make sense of negative numbers, to write algebra expressions, to compute area and volume, and finally to describe a set of data. By June they should be comfortable with signed numbers, one-step equations, decimals in all four operations, basic area/volume/surface area, and describing a data set with center and spread — not as nine separate topics, but as one idea applied nine times.

What your child will learn

The whole year, in plain English. Tap any unit to see every skill inside, nothing is hidden.

Ratios and Rate Reasoningpeek inside ▸

This is where your child learns that comparing two quantities by 'how many times as many' gives different information than comparing by 'how many more.' They'll build ratio tables, double number lines, and move toward unit rates and percents — all as the same underlying idea shown different ways.

  1. Ratio notation and ratio language for a described relationship

    Given a real-world description (e.g. 'for every 3 cups of flour, use 2 cups of sugar'), write the relationship as a ratio using at least two notations (a:b and 'a to b').

  2. The distinction between multiplicative (ratio) and additive (difference) comparison

    Explain why a ratio and a raw count (difference) give different information about the same two quantities, using a specific example.

  3. Ratio table with equivalent ratios generated by scaling

    Complete a ratio table by finding missing values, given one complete row and the multiplicative relationship between rows.

  4. Double number line as a model of a ratio relationship

    Construct a double number line to represent a ratio relationship and use it to find an unknown quantity.

  5. Unit rate comparison across differently formatted representations

    Compare two rates presented in different units or formats (e.g. a table vs. a sentence) and determine which is the better buy or faster rate.

  6. Distinctions among ratio, rate, and unit rate

    Classify a given statement about a ratio relationship as expressing a ratio, a rate, or a unit rate.

  7. Percent as a rate per 100, applied to an unfamiliar context

    Convert a ratio to a percent and interpret percent as a rate per 100 in a context never used during instruction (e.g. a sports statistic or a survey result from a different domain).

  8. Combining two distinct ratio relationships into a single new relationship

    Given a non-routine problem where two ratios must be reasoned about simultaneously (e.g. mixing two batches with different ratios into one), plan a solution strategy and justify why it works.

  9. The general rule for recognizing equivalent ratios across arbitrary tables

    Given two ratio tables built from different contexts, identify the structural feature (constant multiplicative factor) that makes both equivalent ratios, and generalize a rule for recognizing equivalence in any table.

Dividing Fractionspeek inside ▸

Your child already multiplies fractions and used splitting pictures for ratios. Now they learn what dividing by a fraction actually means — two different meanings, in fact — using bar models before any shortcut rule, and only later the 'multiply by the reciprocal' trick, which gets explained rather than handed down.

  1. Measurement (how-many-groups) meaning of division applied to whole ÷ unit fraction

    Given a whole number divided by a unit fraction (e.g. 4 ÷ 1/2), draw a bar model showing how many groups of that fraction fit, and state the quotient.

  2. Measurement meaning of division applied to fraction ÷ fraction

    Draw a bar or number-line model for a fraction ÷ fraction problem (e.g. 2/3 ÷ 1/6) and use it to find the quotient by counting groups.

  3. Common-denominator strategy for fraction division

    Rewrite two fractions with a common denominator and divide by comparing numerators, explaining why this gives the same quotient as the bar model.

  4. Standard algorithm for fraction division

    Execute the standard algorithm (multiply by the reciprocal) to compute a quotient of two fractions or mixed numbers.

  5. Relationship between divisor size and quotient size in fraction division

    Explain, using a partitioning picture, why dividing by a fraction less than 1 produces a quotient larger than the original number.

  6. Measurement versus partitive division situations in word problems

    Classify a word problem as requiring measurement division or partitive division, and select the matching equation.

  7. Fraction division embedded in a ratio/rate context

    Solve a multi-step word problem combining fraction division with a ratio comparison from Unit 1, and justify the choice of operation.

  8. Fraction division applied to a novel real-world context

    Given a fraction division scenario set in an unfamiliar context (e.g. recipe scaling, fabric cutting, fuel consumption) never used in class examples, construct an original bar model and equation to solve it.

  9. Structural equivalence between bar-model and common-denominator justifications of fraction division

    Compare the bar-model justification and the common-denominator justification for the same fraction division problem, and identify what structural feature both share.

The Decimal Systempeek inside ▸

Full standard algorithms for adding, subtracting, multiplying, and dividing decimals — including long division with decimal divisors — plus the discovery that every decimal is really a fraction, some ending, some repeating forever.

  1. Place-value alignment in decimal addition and subtraction

    Given two decimals to the thousandths, add or subtract them correctly by aligning place value, including cases with different numbers of decimal digits.

  2. The structural difference between decimal addition/subtraction and decimal multiplication

    Explain why decimal points must be aligned for addition/subtraction but the decimal point's final position is instead found by counting digits for multiplication.

  3. The standard multiplication algorithm applied to decimals

    Execute the standard algorithm to multiply two multi-digit decimals and place the decimal point correctly by counting total decimal digits.

  4. Decimal division as repeated grouping, connected to fraction division reasoning

    Divide a decimal by a decimal by reframing the problem as whole-number division, using the 'how many groups fit' reasoning from Unit 2 fraction division.

  5. The standard long-division algorithm with decimal dividends and divisors

    Fluently execute the standard long-division algorithm to divide a multi-digit decimal dividend by a multi-digit decimal divisor.

  6. The link between a denominator's prime factors (only 2s and 5s) and whether a decimal terminates

    Classify a given rational number's decimal expansion as terminating or repeating by inspecting the prime factors of the fraction's denominator in lowest terms.

  7. Terminating-decimal-to-fraction conversion via place value, including the reason the pre-simplified denominator is a power of ten

    Convert a terminating decimal to an equivalent fraction in lowest terms using place value of the last digit, and explain why the denominator before simplifying must be a power of ten.

  8. The algebraic method (setting x = the decimal, multiplying to shift the repeat, subtracting) for repeating-decimal-to-fraction conversion

    Generate and justify a method for converting a repeating decimal into an exact fraction, using an algebraic manipulation not directly demonstrated for that specific case.

  9. Estimation strategies applied specifically to decimal operation results

    Estimate the reasonableness of a decimal computation's result using front-end or compatible-number estimation before or after computing exactly.

  10. Multi-step decimal word problems combining two or more of the four operations

    Given a real-world context requiring at least two different decimal operations chained together (e.g. unit pricing with tax and a discount), plan and execute the correct sequence of operations.

Negative Numbers and the Coordinate Planepeek inside ▸

The number line now extends below zero, and points can live in all four quadrants of a coordinate grid, not just the corner your child has used before. Absolute value gets introduced as distance from zero, and reflections and distances-between-points close the unit.

  1. Signed numbers as representations of opposite-direction quantities

    Given a real-world context (temperature, elevation, account balance), write a signed number to represent the quantity and explain what zero means in that context.

  2. The extended number line below zero

    Plot integers and rational numbers, including negatives, on a horizontal or vertical number line.

  3. The relationship between opposite numbers and zero

    Explain why two numbers that are opposites are the same distance from zero but on different sides of it.

  4. Ordering of positive and negative rational numbers

    Compare and order rational numbers, including negatives and negative decimals, using a number line.

  5. Absolute value as distance, independent of sign

    Interpret absolute value as distance from zero and distinguish it from the sign of a number.

  6. Absolute value versus numerical order in context

    Use absolute value and order of rational numbers together to solve a real-world comparison problem, such as ranking account balances or elevations.

  7. The four-quadrant coordinate plane

    Plot ordered pairs with positive and negative coordinates in all four quadrants of the coordinate plane.

  8. Reflections of points across a coordinate axis

    Predict the coordinates of a point reflected across the x-axis or y-axis without plotting first, then verify by plotting.

  9. Horizontal and vertical distance between coordinate points

    Find the distance between two points that share an x-coordinate or y-coordinate by reasoning about absolute value, not by counting grid squares alone.

  10. Four-quadrant coordinate systems as a representational tool

    Design a coordinate-plane map (e.g., a treasure map or city map) using all four quadrants, and write directions using reflections and distances that a partner can follow without seeing the original map.

Expressions with Variablespeek inside ▸

Your child moves from arithmetic with known numbers to arithmetic with a variable — a letter standing for a number that can change. They'll translate word phrases into symbols, evaluate expressions with signed and fractional values, meet exponents as repeated multiplication, and use the distributive property to build and prove equivalent expressions.

  1. The structural parts of an algebraic expression (coefficient, variable, term, constant)

    Identify the coefficient, variable, and constant term in a given one- or two-term expression.

  2. The correspondence between verbal quantity language and symbolic expressions

    Translate a word phrase describing a real quantity (e.g., 'five more than three times a number') into an algebraic expression.

  3. Substitution of signed values into an expression using order of operations

    Evaluate an algebraic expression by substituting a given negative integer or fraction for the variable and applying order of operations.

  4. The structural meaning of exponential notation as repeated multiplication

    Explain why an exponent represents repeated multiplication rather than repeated addition or multiplication by the exponent.

  5. Numerical expressions containing exponents evaluated with order of operations

    Evaluate numerical expressions involving whole-number exponents, including within a larger expression using order of operations.

  6. The distributive property applied to expressions with a variable term and a constant term

    Generate an equivalent expression for a given expression by applying the distributive property to a sum or difference inside parentheses.

  7. Equivalence of algebraic expressions verified through both numeric testing and structural comparison

    Determine whether two given expressions are equivalent by evaluating both at several values, including a negative and a non-integer value, and by comparing their structure.

  8. The logical distinction between numeric verification and general proof of expression equivalence

    Construct a general argument, using an area model or algebraic reasoning, that a(b+c) and ab+ac are equivalent for any value of the variable, not merely for values tested.

  9. The non-equivalence of (x+y)^2 and x^2+y^2 as a case where surface-level distribution fails

    Determine whether the claim '(x+y)^2 = x^2+y^2' is true for all values of x and y, using a counterexample and an area-model explanation of the error.

Equations and Proportional Relationshipspeek inside ▸

An equation is a balance — whatever you do to one side, you must do to the other. Your child learns to solve one-step equations with all four operations, translate word problems into equations, and recognize when a table of values represents a proportional relationship, writing it as y = kx and graphing it.

  1. One-step addition and subtraction equations solved using the balance model

    Given a one-step addition or subtraction equation, the student solves for the unknown by applying the same inverse operation to both sides.

  2. One-step multiplication and division equations solved using the balance model

    Given a one-step multiplication or division equation, the student solves for the unknown by applying the same inverse operation to both sides.

  3. The balance model of equation equality

    The student explains why performing an operation on only one side of an equation breaks equality, using the balance model.

  4. One-step equations translated from word-problem contexts

    Given a short word problem describing a real quantity and an unknown, the student writes a one-step equation that represents the relationship.

  5. Reversal errors in translating comparison sentences to equations

    The student identifies which of two equations correctly models a comparison word problem prone to a reversal error, and justifies the choice by substituting a numeric value.

  6. Proportionality tested via constant ratio across a table

    Given a table of paired values, the student determines whether the relationship is proportional by checking whether the ratio y/x is constant across multiple rows.

  7. Independent and dependent variables in a two-quantity relationship

    The student distinguishes the independent variable from the dependent variable in a given real-world scenario and assigns each to the correct axis.

  8. The constant of proportionality k in y = kx

    Given a proportional relationship in context, the student writes the equation y = kx and states what k represents in that context.

  9. Graphs of proportional relationships used for prediction beyond given data

    Given a proportional relationship, the student graphs it on a coordinate plane and uses the graph to predict an untabulated value.

  10. Invariance of the graph of y = kx under changing real-world context

    The student generalizes across two different proportional contexts to explain why relationships with the same constant of proportionality produce identical graphs regardless of context.

Area, Surface Area, and Volumepeek inside ▸

Finding area of triangles, parallelograms, and trapezoids by breaking them into shapes already known, unfolding 3D solids into flat nets to find surface area, and finding volume of rectangular prisms with fractional edges. The same move — break it down into something familiar — repeats throughout.

  1. Area of a triangle via decomposition into a rectangle/parallelogram

    Find the area of a triangle by decomposing or rearranging it into a rectangle or parallelogram of known area.

  2. Conservation of area under decomposition and rearrangement

    Explain why decomposing a shape into pieces and rearranging those pieces never changes the shape's total area.

  3. Area of a trapezoid via decomposition

    Find the area of a trapezoid by decomposing it into a rectangle and two triangles, or into two congruent trapezoids forming a parallelogram.

  4. Area of a polygon on the coordinate plane

    Find the area of an irregular polygon plotted on a coordinate plane by decomposing it into triangles and rectangles using the vertex coordinates.

  5. Surface area of a composite solid built from familiar solids

    Given the surface area of an unfamiliar composite solid (not a simple prism) built from known solids, plan a decomposition strategy and justify it before computing.

  6. Nets of right rectangular prisms

    Construct a net that represents the faces of a given right rectangular prism, correctly matching each face's dimensions.

  7. Surface area of prisms via nets

    Calculate the surface area of a right rectangular prism or triangular prism by summing the areas of all faces shown in its net.

  8. Net design against a surface-area constraint

    Design a net for a right rectangular prism that meets a specified total surface area target, and justify that the design is correct.

  9. Volume of a right rectangular prism with fractional edge lengths

    Calculate the volume of a right rectangular prism with fractional edge lengths using the formula V = l x w x h.

  10. Effect of fractional multiplication on volume magnitude

    Compare a prediction about how fractional edge lengths affect volume to the actual computed volume, and reconcile any mismatch.

  11. Distinguishing area, surface area, and volume in context

    Classify a real-world measurement scenario as requiring area, surface area, or volume based on what physical quantity is being measured.

  12. Surface area formula as an algebraic expression with a variable edge

    Write and evaluate an algebraic expression for the surface area of a rectangular prism with one unknown edge length.

Statistical Distributionspeek inside ▸

The year closes with describing a set of data by its shape, center, and spread together, not just one number. Your child will build dot plots, histograms, and box plots, compute mean, median, range, and MAD, and use all of it to compare two data sets with the same average but very different stories.

  1. The distinction between statistical and non-statistical questions

    Given a list of questions, classify each as a statistical question or not, justifying the classification by naming expected variability in possible answers.

  2. Dot plots as a graphical representation of a data set

    Construct a dot plot from a given small data set (9-15 values), correctly plotting each value above a labeled number line.

  3. The median as a measure of center

    Compute the median of an ordered data set, correctly applying the different rule for odd versus even counts of values.

  4. Mean absolute deviation as a measure of variability

    Compute the mean absolute deviation (MAD) of a data set and explain what the resulting number indicates about spread around the mean.

  5. Shape of a distribution as shown across two different graph types

    Given a histogram and a box plot of the same data set, compare the shape of the distribution described by each, identifying clusters, gaps, and skew.

  6. The relationship between center, spread, and what counts as a 'typical' or 'consistent' value

    Given two data sets with equal means but different spreads, construct an argument for which set is more consistent, using a computed measure of variability as evidence.

  7. The potential for a summary statistic to misrepresent a distribution

    Given an unfamiliar real-world data set (e.g. city rainfall totals) never discussed in class, decide which measure of center would most mislead a reader and justify the choice.

  8. A complete statistical comparison of two distributions

    Given a real or provided data set, produce two different graphical representations (from dot plot, histogram, box plot) and a written comparison of two distributions using center and spread.

  9. The insufficiency of a single summary statistic to characterize a distribution

    Given a claim like 'these two classes performed the same because they have the same mean,' identify what information is missing and explain why the claim is incomplete.

From the parent guide

This is the year your child learns to think in ratios instead of just counting differences — "for every 3 of these, 2 of those" instead of "3 more of these." That one idea (a multiplicative relationship between two quantities) gets used all year: to divide fractions, to make sense of negative numbers, to write algebra expressions, to compute area and volume, and finally to describe a set of data. By June they should be comfortable with signed numbers, one-step equations, decimals in all four operations, basic area/volume/surface area, and describing a data set with center and spread — not as nine separate topics, but as one idea applied nine times.

Unit 1 · what to expect

This is where your child learns that comparing two quantities by 'how many times as many' gives different information than comparing by 'how many more.' They'll build ratio tables, double number lines, and move toward unit rates and percents — all as the same underlying idea shown different ways.

The full guide covers all 8 units: where kids get stuck, what to say, and how to tell it's working. Included with the course.

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Ratios, Relationships, and the Number System, Grade 6 Homeschool Curriculum