Addition & Subtraction

From combining sets to multi-digit written methods — 52 skills across 9 years. Every skill below shows what it builds on and how to tell your child has it.

Mathematics52 skillsages 4–13

Grouped by the age children typically start each skill. Ages are typical, not deadlines — follow your child’s pace.

Around age 4

Addition and subtraction word problemsages 4–6AC ✓ Addition as combining or putting together twoages 4–6AC ✓ Number bonds to 9ages 4–6AC ✓ Numbers up to 10 into pairsages 4–6AC ✓ Representing Addition and Subtractionages 4–6AC ✓ Subtraction as taking away or separatingages 4–6AC ✓

Around age 5

Adding and subtractingages 5–6AC ✓ Early Word Problemsages 5–7AC ✓ Fluent adding and subtracting within 5ages 5–6AC ✓ Number bondsages 5–6AC ✓ Reading +, −, and = symbolsages 5–6AC ✓

Around age 6

Adding and subtracting tens mentallyages 6–7AC ✓ Adding Three Small Numbersages 6–7AC ✓ Adding two two-digit numbersages 6–7AC ✓ Adding within 100ages 6–7AC ✓ Addition and subtraction strategiesages 6–7AC ✓ Addition and subtraction within 20ages 6–7AC ✓ Addition in any orderages 6–7AC ✓ Finding a missing number in additionages 6–7AC ✓ Fluent adding and subtracting within 10ages 6–7AC ✓ Fluent addition and subtractionages 6–7AC ✓ Grouping numbers to addages 6–7AC ✓ Inverse: addition undoes subtractionages 6–7AC ✓ Mental addition and subtraction (age 6+)ages 6–7AC ✓ Mental and written addition and subtractionages 6–7AC ✓ Subtracting multiples of 10ages 6–7AC ✓ Unknown in Addition & Subtractionages 6–7AC ✓ What the equals sign meansages 6–7

Around age 7

Adding and subtracting (age 7+)ages 7–8AC ✓ Adding numbersages 7–8AC ✓ Addition and subtraction strategies (age 7+)ages 7–8AC ✓ Addition and subtraction within 1000ages 7–8AC ✓ Estimating by roundingages 7–9AC ✓ Fluent adding and subtracting within 100ages 7–8AC ✓ Fluent adding and subtracting within 20ages 7–8AC ✓ Mental addition and subtraction (age 7+)ages 7–8AC ✓ Mentally adding hundreds to 3-digit numbersages 7–8AC ✓ Mentally adding tens to 3-digit numbersages 7–8AC ✓ Missing number problems (age 7+)ages 7–8AC ✓ Numbers on a number lineages 7–8AC ✓ Two-Step Word Problemsages 7–8AC ✓

Around age 8

Adding and subtracting (age 8+)ages 8–9AC ✓ Fluent adding and subtracting within 1000ages 8–9AC ✓ Two-step addition and subtraction problemsages 8–9AC ✓ Two-Step Equationsages 8–9AC ✓

Around age 9

Adding and subtracting (age 9+)ages 9–10AC ✓ Checking Answers by Roundingages 9–10AC ✓ Fluent addition and subtraction (age 9+)ages 9–10AC ✓ Mental addition and subtraction (age 9+)ages 9–10AC ✓

Around age 10

Adding and subtracting (age 10+)ages 10–11AC ✓ Addition and subtraction strategies (age 10+)ages 10–11AC ✓

Around age 11

Positive and Negative Numbersages 11–13AC ✓

Algebra → · more Mathematics domains