Addition by Partitioning

Worked Examples of Addition by Partitioning

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In Years 3/4 children start to lay out numbers to be added vertically, to get ready for the introduction of column addition typically in Years 5/6.
When two-digit numbers are to be added, children are usually taught to add the tens first which gives a rough answer, and then add the units and add those to the total of the tens.
For three-digit numbers, the hundreds are added first, then the tens, and then the units.

Vertical Addition by Partition with 2-digit Numbers   69 + 76  130  (60 + 70) Add the tens   15  (9 + 6)   Add the units  145 Vertical Addition by Partition with 3-digit Numbers   639 + 364   900  (600 + 300) Add the hundreds    90  (30 + 60)  Add the tens    13  (9 + 4)    Add the units  1003

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