n × 99
The trick, step by step
Multiply by 100: 34 × 100 = 3400.
Take away one 34: 3400 − 34 = 3366.
So 34 × 99 = 3366.
given working answer taken away
Why it works
99 is one less than 100, so n × 99 = n × 100 − n.
Practise this trickTricks · Multiplying
Multiply by 99
Any number times 99, such as 34 × 99.