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

+ 52
 130  (80 + 50) Add the tens
   9  (7 + 2)   Add the units

Vertical Addition by Partition with 3-digit Numbers

+ 704
 1200  (500 + 700) Add the hundreds
   60  (60 + 0)  Add the tens
   12  (8 + 4)    Add the units

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