Decimal Calculations 3
Multiplication of Whole Numbers

Here we start with multiplication of whole numbers, which is a useful technique for all sorts of problems.

You should know your multiplication tables up to 10 x 10, but for revision, we include these here.

Worked Examples

1

Jai spends £3 on sweets each week for 7 weeks. Calculate how much he spends altogether.

Show me

He spends (in £) 3 + 3 + 3 + 3 + 3 + 3 + 3 (= 21), but it is easier to calculate

3 x 7 = 21 is £21.

Exercises

Find

(a)
2 × 3
(b)
5 × 7
(c)
6 × 3
(d)
3 × 7
(e)
5 × 4
(f)
9 × 2
(g)
8 × 5
(h)
6 × 6
(i)
9 × 4
(j)
8 × 7
(k)
9 × 8
(l)
7 × 9
(m)
6 × 7
(n)
9 × 9
(o)
8 × 6

Is each of these statements true or false?

(a)
5 × 4 = 4 × 5
(b)
6 × 5 = 6 × 7
(c)
8 × 9 = 4 × 36
(d)
21 × 5 = 7 × 15

Jamil saves £5 per month from his pocket money.

(a)

How much does he save in 4 months?

£
(b)

How long will it take him to save £30?

months

How many bottles are there in this crate?

bottles

Emma, Rachel, Sarah and Hannah go to a disco. It costs £3 each to get in.
How much do they pay altogether?

£

The picture shows the tiles on one wall in Sophia's bathroom.
How many tiles are on this wall?

tiles

Packets of chewing gum are packed in a box. In a box there are 8 layers with 9 packets of chewing gum in each layer.
How many packets are there in the box?

packets

A hotel has 9 floors. On each floor there are 7 windows.
How many windows are there in the hotel?

windows