19199 x 19199 = 368601601  and so on.
960960921600

Many adopt the following method:—

£20 x £20 = £400

¼d x ¼d = 116  less£  s   d  Ans.
£400 0   0
     116
£399 19 11 1516

It would be possible to adopt other methods, each of which would give a different result.

Properly speaking, this sum cannot be done.

Multiplication is merely a contracted form of addition: it means taking a number or quantity a certain number of times. Every multiplication can be proved by addition. All numbers are abstract or concrete—3 is abstract, £3 is concrete.

Two abstract numbers can be multiplied together—as, 4 times 3 = 12.

One abstract number and one concrete number can be multiplied together—as 2s. multiplied by 3 = 6s.