# Addition and subtraction: numbers to 100 and 1,000

This guide provides a sequence of steps for exploring and developing addition and subtraction strategies, including an emphasis on not crossing 10s and 100s and crossing 10s and 100s.

Year level(s) Year 2, Year 3, Year 4, Year 5, Year 6
Audience Teacher
Purpose Teaching resource, Teaching strategies
Teaching strategies and pedagogical approaches Questioning, Concrete Representational Abstract model, Explicit teaching
Keywords add, subtract, addition, subtraction, multiples of 100, bar model, part-whole model, reasoning, problem-solving, number tracks,, calculations, place value, place value grid, 2-digit numbers, 3-digit numbers, base 10 blocks, explicit teaching

## Curriculum alignment

Curriculum connections Numeracy
Strand and focus Number, Build understanding
Topics Addition and subtraction, Place value, Operating with number
AC: Mathematics content descriptions
ACMNA030 Solve simple addition and subtraction problems using a range of efficient mental and written strategies
ACMNA055 Recall addition facts for single-digit numbers and related subtraction facts to develop increasingly efficient mental strategies for computation
ACMNA073 Apply place value to partition, rearrange and regroup numbers to at least tens of thousands to assist calculations and solve problems
ACMNA099 Use estimation and rounding to check the reasonableness of answers to calculations
ACMNA291 Use efficient mental and written strategies and apply appropriate digital technologies to solve problems
ACMNA123 Select and apply efficient mental and written strategies and appropriate digital technologies to solve problems involving all four operations with whole numbers