Starter quiz
- What is an addend?
- An addend is a number multiplied by a number.
- An addend is a number added to another. ✓
- An addend is a number subtracted from another.
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- What should you add to 70 to make 100?
- '30' ✓
- What would you add to 92 to make 100?
- '8' ✓
- 92 + 14 = ______
- '106' ✓
- ______ = 107 − 9
- '98' ✓
The bucket balance has been filled with marbles and blocks. It is balanced. Which of these most closely represent the equation shown by the bucket balance?- 2 + 2 = 2 + 2
- 2 + 3 = 2 + 3
- 2 + 3 = 4 + 1 ✓
- 3 + 2 = 1 + 4 ✓
- 3 + 3 = 2 + 4
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Exit quiz
Which group has a different number of 'units'?- 'Pandas' ✓
- Match the units with their value.
- 3 tens⇔30 ✓
- 3 hundreds⇔300 ✓
- 3 ones⇔3 ✓
- 4 tens⇔40 ✓
- 5 hundreds⇔500 ✓
- 7 ones⇔7 ✓
- Match the expressions.
- 4 + 5⇔4 ones + 5 ones ✓
- 4 tens + 5 tens⇔40 + 50 ✓
- 4 hundreds + 5 hundreds⇔400 + 500 ✓
- 32 + 54⇔32 ones + 54 ones ✓
- 32 tens + 54 tens⇔320 + 540 ✓
- 450 + 390⇔45 tens + 39 tens ✓
- 130 + 150 = ______
- '280' ✓
- Match the expressions with the most relevant strategy for mental addition.
- 407 + 380⇔Partitioning ✓
- 150 + 110⇔Unitising ✓
- ______ = 211 + 450
- '661' ✓
Worksheet
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Presentation
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Lesson Details
Key learning points
- Partitioning can be used to add 3-digit numbers
- Unitising means we can use known facts to add larger numbers. For example, 370 + 260 is equal to 37 tens add 26 tens.
Common misconception
Pupils may not understand that a tens counter has a value of ten. For example, they may think that 14 tens and 11 tens make 25 altogether, forgetting to convert 25 tens into 250.
Encourage counting in tens using counters to begin with. Move onto modelling questions using base ten so the children can count the tens blocks.
Keywords
Addend - An addend is a number added to another.
Sum - The sum means the total when the numbers are added together.
Unitising - Unisiting means treating groups that contain the same number of things as 'ones' or 'units'.
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