The minuend is the number being subtracted from.

A subtrahend is a number subtracted from another.

The difference is the result after subtracting one number from another.

When you adjust you make a change to a number. This is done to make a calculation easier to solve mentally.

Calculate the difference using knowledge of an adjusted subtrahend: difference structure

Maths

In this unit pupils will explain how increasing or decreasing the minuend affects the difference and solve subtraction calculations mentally using known facts explaining how adjusting the minuend can make mental calculation easier In the future unit pupils will explain how to balance equations with addition or subtraction expressions and use their knowledge of balancing equations to solve problems

In the prior unit pupils used the concept of same sum to simplify and solve addition problems  In this unit pupils will explain how increasing or decreasing the minuend affects the difference and solve subtraction calculations mentally by using known facts explaining how adjusting the minuend can make mental calculation easier

Use equivalence and compensation to simplify and solve subtraction problems

Jun and Laura are flipping coins and recording the results as they go. They each flip the coin 72 times. The table shows how many they each got except one blank cell. How many tails did Laura get?

Jun and Laura are flipping coins and recording the results as they go. They each flip the coin 150 times. The table shows how many they each got except one blank cell. How many heads did Jun get?

Jun and Laura each take the same number of shots at the goal ring in netball. Jun scores 20    Laura scores 17 but misses 18    How many did Jun miss? {{ }} misses

Jun and Laura each take the same number of shots at the goal ring in netball. Laura misses 32 and scores 21   Jun misses 16 only. How many did Jun score? Jun scored {{ }}

Look at the pair of equations and use the complete one to help find the missing number in the second.

Look at the pair of equations below and use the complete one to help find the missing number in the second.

If the subtrahend is 262, which part of the bar model below is the difference?

Solve the following calculation mentally by adjusting the minuend and subtrahend.
285 − 77 = {{ }}

Solve the following calculation mentally using unitisation.
{{ }} = 3,900 − 1,300

Solve the following calculation mentally by adjusting the minuend and then the difference.
4,008 − 1,300 = {{ }}

Solve the following calculation using a mental strategy.
{{ }} = 703 − 146

Look at the jottings. What was the value of the adjustment to the subtrahend and the difference?

This lesson will soon be taken down.

Calculate the difference using knowledge of an adjusted subtrahend: difference structure

Lesson outcome