Starter quiz
What is the missing part in this bar model?- '360' ✓
- 134 + 99 = ______
- '233' ✓
- Jun buys two packs of apples which cost £1.99 each. How much does he spend altogether? Jun spends £______
- '3.98' ✓
- Sofia has £5 to spend. She spends £3.50 on a ball. How much change should she receive?
- '£1.50' ✓
What is the missing part in this bar model?- '375' ✓
- Andeep thinks of a 2-digit number. He adds 10 before doubling it to finish with the number 44 What was his starting number?
- 10
- 11
- 12 ✓
- 13
-
Exit quiz
Is the question mark on the bar model a part or whole?- part ✓
- whole
-
- Use the mental strategy of redistribution to calculate the sum. 34 + 29 = ______
- '63' ✓
- Use the mental strategy of redistribution to calculate the sum. 69 + 45 = ______
- '114' ✓
- Use the mental strategy of redistribution to calculate the sum. 20,999 + 7,573 = ______
- '28,572' ✓
- Which of these additions do you think was most likely to have been solved using redistribution?
- 190 + 456 = 646 ✓
- 347 + 283 = 630
-
- Which inequality symbol should be placed between these two addition expressions? Use redistribution to help. 2,002 + 10,567 ______ 1,997 + 10,574
- < ✓
- =
- >
-
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- If one part is increased and the other is decreased by the same amount, the whole stays the same.
- If one part is decreased and the other is increased by the same amount, the whole stays the same.
- Redistributing between parts with the whole staying the same is sometimes known as the 'same sum' rule.
Common misconception
Lots of children will want to make use of a written method such as column addition straight away without considering the use of mental methods with jottings.
Encourage the children out of their comfort zone by praising efforts and allowing them to feel motivated by any small successes in the method. Explain to them that this understanding will help them to be better mathematicians in the long run!
Keywords
Redistribution - Redistribution is where part of one addend is moved to another addend. It is sometimes known as the same sum rule.
Sum - The sum is the total when numbers are added together.
Whole - The whole is all the parts or everything, the total amount.
Part - A part is some of the whole.
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