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   79 + 83  150  (70 + 80) Add the tens   12  (9 + 3)   Add the units  162 Vertical Addition by Partition with 3-digit Numbers   408 + 952  1300  (400 + 900) Add the hundreds    50  (0 + 50)  Add the tens    10  (8 + 2)    Add the units  1360

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