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   30 + 48   70  (30 + 40) Add the tens    8  (0 + 8)   Add the units   78 Vertical Addition by Partition with 3-digit Numbers   600 + 191   700  (600 + 100) Add the hundreds    90  (0 + 90)  Add the tens     1  (0 + 1)    Add the units   791

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