In this activity, we will multiply numbers by amounts such as £1.99 or £2.99 or £3.99 etc.
This is particularly useful when you go shopping.
17 × £2.99
First, we pretend that the amount is £3 and not £2.99
Multiply 17 by £3 to get £51
This is 17 × 1p too much, so we now subtract 17p from £51
£51.00 - 17p = £51.00 - £0.17 = £50.83
So 17 × £2.99 = £50.83
Alternatively, we can just do our normal multiplication calculation by removing the decimal point, doing the multiplication and then putting the decimal point back in, making sure that we have the same number of decimal places in our answer as in the original calculation.
17 x £2.99 had two decimal places.
17 x 299 = 5083
Put the decimal point back in to give two decimal places: 50.83
The answer is £50.83
Note that answers will have two decimal places if we are doing calculations with money!
Let's have a go at these questions now.