Subtract a pair of 2-digit numbers by finding the difference

Maths

In this unit pupils will add and subtract two 3-digit numbers using partitioning, adjusting, redistribution and bridging. In the future unit pupils will accurately and efficiently solve multi-step addition and subtraction problems. They will understand and explain how both addition and subtraction equations can be used to describe the same additive relationship.

In the prior unit pupils found pairs of number that composed 100 and positioned 3-digit numbers on a number line and estimated their position on unmarked number lines. They compared and ordered 3 digit numbers. In this unit pupils will add and subtract two 3-digit numbers using partitioning, adjusting, redistribution and bridging

Informal and mental strategies for adding and subtracting two 3-digit numbers

Match the numbers with words for the equation 8 − 6 = 2

Which of these bar models represents finding the difference?

How many more sweets do I have compared to you?

Which of these contexts does not involve finding the difference?

Which of these subtraction expressions can be more efficiently solved by finding the difference?

What number is represented by these place value counters?

What number is represented by the base ten blocks?

Choose the correct symbol to go between the expressions.  7 + 5 ___ 3 + 4

Choose the correct symbol to go between the expressions. 20 − 3 ___ 12 + 10

Choose the correct symbol to go between these expressions. 34 − 10 ___ 14 + 10

Using your understanding of place value, order these numbers from smallest to greatest.

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Subtract a pair of 2-digit numbers by finding the difference

Lesson outcome