Subtraction — Victorian Year 3 Maths
Mental strategies first, then written subtraction of two- and three-digit numbers, with and without regrouping, and subtracting across zeros. Five subtopics and 100 questions, aligned to VC2M3A02 and VC2M3N04.
Subtraction in Victorian Year 3
Subtraction finds what is left, or how far apart two numbers are. This topic takes Year 3 students from mental strategies to written methods for two- and three-digit numbers, including regrouping and subtracting from numbers with zeros.
The five subtopics below cover mental strategies for subtraction, subtracting two-digit numbers without and then with regrouping, subtracting three-digit numbers, and subtracting across zeros. Subtraction is one of the 18 topics in Victorian Year 3 Maths and draws on the Number and Algebra strands. It covers Victorian Curriculum 2.0 codes VC2M3A02 and VC2M3N04. Subtraction pairs with Addition, and both are put to work in Addition and Subtraction Problems and in Money, where change is worked out.
Subtopics
Subtraction: common questions
How do you subtract when the top digit is smaller?
Regroup. In \(72 - 45\) you cannot take 5 from 2, so trade 1 ten for 10 ones: 72 becomes 6 tens and 12 ones. Then 12 take away 5 is 7, and 6 tens take away 4 tens is 2 tens, so the answer is 27.
How do you subtract from a number with zeros, like 600?
Change 1 hundred into 10 tens, then 1 ten into 10 ones. For \(600 - 258\), 600 becomes 5 hundreds, 9 tens and 10 ones, and the answer is 342. Counting up also works: from 258 to 300 is 42, then 300 more makes 342.
What is the most common subtraction mistake?
Taking the smaller digit from the larger in every column, whichever is on top. For \(62 - 38\) this gives 36 instead of 24. Ask your child to check by adding: \(24 + 38 = 62\), so 24 is right.
How can we practise subtraction at home?
Work out change when shopping, count down the days to a birthday, or find how many more points one team needs to catch another. Counting up from the smaller number is a good mental check, and estimating first shows whether an answer is sensible.
Which curriculum codes cover Subtraction in Victorian Year 3?
The subtopics come under Victorian Curriculum 2.0 codes VC2M3A02 (mental strategies built on known addition and subtraction facts) and VC2M3N04 (adding and subtracting by splitting and regrouping numbers by place value).