Addition by Partitioning




Worked Examples of Addition by Partitioning

Click here to return to Mental Arithmetic homepage.

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

  10
+ 38
  40  (10 + 30) Add the tens
   8  (0 + 8)   Add the units
  48



Vertical Addition by Partition with 3-digit Numbers

  394
+ 117
  400  (300 + 100) Add the hundreds
  100  (90 + 10)  Add the tens
   11  (4 + 7)    Add the units
  511


Press F5 or click here to see more examples of addition by partitioning.

Buy mental maths workbooks for children - books for sale


All worksheets published online at Mental-Arithmetic.co.uk are free to print without modification
for non-commercial use by schools, children, parents, and care givers.
2010-2018 Mental-Arithmetic.co.uk - All Rights Reserved