Add two 3-digit numbers using partitioning
I can add two 3-digit numbers using partitioning.
Add two 3-digit numbers using partitioning
I can add two 3-digit numbers using partitioning.
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.
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'.
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.
Equipment
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.What is an addend?
Q2.What should you add to 70 to make 100?
Q3.What would you add to 92 to make 100?
Q4.92 + 14 =
Q5. = 107 − 9
Q6.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?
Assessment exit quiz
6 Questions
Q1.Which group has a different number of 'units'?
Q2.Match the units with their value.
30
300
3
40
500
7
Q3.Match the expressions.
4 ones + 5 ones
40 + 50
400 + 500
32 ones + 54 ones
320 + 540
45 tens + 39 tens
Q4.130 + 150 =
Q5.Match the expressions with the most relevant strategy for mental addition.
Partitioning
Unitising