Starter quiz
- In the following equation, which number is the difference? 38 − 12 = 26
- 38
- 12
- 26 ✓
-
- Solve the following calculation mentally by adjusting the minuend and subtrahend. 157 − 32 = ______
- '125' ✓
- Solve the following calculation mentally using unitisation. ______ = 290 − 120
- '170' ✓
- Solve the following calculation mentally by adjusting the subtrahend and then the difference. 1,050 − 902 = ______
- '148' ✓
- Solve the following calculation using a mental strategy. ______ = 211 − 97
- '114' ✓
- 7,261,000 − 11,000 = ______
- '7,250,000' ✓
Exit quiz
- Find the missing number in the equation below by adjusting the minuend to match the ones digit of the subtrahend. 153 − 36 = ______
- '117' ✓
- Find the missing number in the equation below by adjusting the minuend to match the ones digit of the subtrahend ______ = 269 − 46
- '223' ✓
- Find the missing number in the equation below by adjusting the minuend to match the ones digit of the subtrahend. 2,887 − 44 = ______
- '2,843' ✓
- Find the missing number in the equation below by adjusting the minuend to match the ones digit of the subtrahend. 1,567 − 59 = ______
- '1,508' ✓
- Find the missing number in the equation below by adjusting the minuend. 3,084 − 0.46 = ______
- '3083.54' ✓
- Find the missing number in the equation below by adjusting the minuend. ______ = 967,000 − 35,000
- '932,000' ✓
Worksheet
Loading worksheet ...
Presentation
Loading presentation ...
Video
Lesson Details
Key learning points
- If you increase the minuend the difference increases by the same amount.
- If you decrease the minuend the difference decreases by the same amount.
- Partitioning the minuend can simplify the calculation.
Common misconception
Pupils may be eager to use columnar written methods for larger integers and decimals instead of considering the values and using an efficient strategy.
Emphasise the importance of trying different mental methods so that pupils aren't reliant on written methods that prevent them from fully grasping the underlying structure of additive problems.
Keywords
Minuend - The minuend is the number being subtracted from.
Subtrahend - A subtrahend is a number subtracted from another.
Adjust - When you adjust you make a change to a number. This is done to make a calculation easier to solve mentally.
Inverse - The inverse is the opposite or reverse operation. For example, subtraction is the inverse operation of addition.
+