Zero in written multiplication

When the written multiplication method is introduced, pupils may display a lack of confidence in multiplying with zero, or may not understand the importance of zero as a place holder.

In this calculation, the pupil has seen the zero in the tens column and realised that 0 x 3 = 0, or ‘nothing’, and as a result, has recorded nothing in the tens column. Reinforcing the importance of zero as a placeholder, as well as zero being ‘nothing’, will enable the pupil to maintain the place value of the digits.

A pupil may fail to use a placeholder if multiplying digits results in an answer ending in zero. Here, the pupil has worked out that 5 x 8 (in the tens column) = 40, but has not realised the importance of this being 40 tens. Instead, they have combined this mentally with the 5 units to give an answer of 45.

Similarly, in this calculation, 8 x 7 (tens) = 56, then adding on the carried 4 (tens) gave an answer of 60. Again, this was viewed mentally as 60, rather than 60 tens and a place holder was not used, giving an incorrect answer of 68.

Estimating the approximate size of an answer can help pupils to recognise such errors with place value. For example, using 70 x 8 = 560 to realise that 76 x 8 will be much larger than 68.