Starter quiz
How many pentagons are there in this group of polygons?- 1
- 2
- 3 ✓
- 4
- 5
-
- What is the product of 2 and 10?
- '20' ✓
- ______ = 15 − 9
- '6' ✓
- ______ = 25 − 19
- 6 ✓
- six ✓
-
- Which of the following expressions give a difference of six?
- 26 − 19
- 10 − 4 ✓
- 100 − 4
- 27 − 10
- 13 − 7 ✓
-
- 207 − 190 = ______
- '17' ✓
Exit quiz
- Which is the correct definition of difference?
- The result after adding one number to another.
- The result after multiplying two or more numbers.
- The result after dividing one number by another.
- The result after subtracting one number from another. ✓
-
What subtraction equation does this number line represent?- 75 + 24 = 99
- 75 − 20 = 55
- 75 − 24 = 51 ✓
- 75 − 51 = 24
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- Find the difference between 270 and 160 using partitioning.
- '110' ✓
- Find the difference between 430 and 310 using partitioning.
- '120' ✓
- Find the difference between 540 and 360 using partitioning and bridging.
- '180' ✓
- Find the difference between 670 and 490 using partitioning and bridging.
- '280' ✓
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- By looking at the minuend and subtrahend we know if we will have to bridge 10 or 100
- If the ones digit of the subtrahend is greater than the ones digit of the minuend then we will have to bridge through 10
- If the 10s digit of the subtrahend is greater than the 10s digit of the minuend then we will have to bridge through 100
Common misconception
Pupils will often try to use a written method/algorithm which they know gives an accurate answer but don't understand why it works.
Encourage the pupils to be brave and remind them that this is about mental subtraction so, with practice, will be quicker than any written methods.
Keywords
Minuend - The minuend is the number being subtracted from.
Subtrahend - A subtrahend is a number subtracted from another.
Difference - The difference is the result after subtracting one number from another.
Partition - Partition is the act of splitting an object or value down into smaller parts.
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