The method traditionally used for multiplying two numbers of two or more digits is long multiplication
, but this is quite an abstract process which is difficult to understand for many children. Grid Multiplication
(also known as the Grid Method
) is now taught in schools as an intermediate stage before long multiplication.
With grid multiplication
, the two numbers to be multiplied are split (partitioned
) up into their tens and units components - e.g. 34 = 30 + 4, or hundreds, tens, and units components - e.g. 345 = 300 + 40 + 5. (Click here for our 2-digit number partitioning worksheets
and 3-digit number partitioning worksheets
for partitioning practice)
The grid method
enables a complex multiplication to be broken up into a collection of relatively simple multiplications followed by some column addition
Grid Method Example
54 x 12 can be partitioned
to give us (50 + 4) x (10 + 2)
this can be expanded to four simple multiplications which when added together give the final answer: (50 x 10) + (50 x 2) + (10 x 4) + (4 x 2).
This is done with the use of a grid
as shown below:
Total up the columns and write the totals in the row at the bottom of the grid. Then finally add together those totals for the final answer. Here 54 x 12 = 540
The Grid Method can
be used to multiply very large numbers using a larger grid, but by the time a child is confident multiplying 3- and 4- digit numbers using grid multiplication, they are ready for long multiplication which is a faster method.
TU x U Grid Multiplications - Pre-Partitioned
For this introduction to grid multiplication, numbers of type TU are multiplied by numbers of type U, for example 37x4
. The TU part is provided in the grid ready partitioned, so that the focus is on doing the multiplications and adding the results together for the final answer using the Grid Method.
Next move on to either Grid Multiplication TUxTU Partitioned
for more complicated multiplications ready partitioned in the grid, or Grid Multiplication TUxU
to try TUxU type multiplications where partitioning and grid set up need to be done by the child.