When working with decimal values, it is important to ensure that the decimal point remains in the same position (column) throughout the calculation. This is easier if the same number of decimal places (i.e. positions to the right of the decimal point) are used for each value in the calculation.
When working with money, in mixed values of pounds and pence, include a decimal point and two decimal places in each line of the calculation.
Two zeros after the decimal indicate ‘no pence’ and a zero before the decimal point indicates ‘no pounds’.
For example, to subtract £6.05 (six pounds and five pence) from £13 (thirteen pounds):
Remember that 1 in any position is worth 10 when added to the column immediately to its right.
The tens column now only contains 0, so this is the end of the process.
It is easier to ensure an accurate result if you use the same number of decimal places (positions to the right of the decimal point) for both values in the calculation, inserting zeros in any which are not required.
For example to subtract 17.5 from 24.247: