Product 100

Age 11 to 14

ShortChallenge Level Yellow star

Answer: 18

100 = 50

$\times$ 2

$\times$ 1

$\times$ 1 not all different
= 10

$\times$ 5

$\times$ 2

$\times$ 1 good! Sum = 18

Is there another way?
Factors of 100 not used: 4, 20, 25

100 = 4

$\times$ 25

$\times$ 1

$\times$ 1 not all different
= 4

$\times$ 5

$\times$ 1 not all different. Cannot use 4
= 25

$\times$ 2

$\times$ 1 not all different. Cannot use 25
100 = 20

$\times$ 5

$\times$ 1

$\times$ 1 not all different. Cannot use 20

This problem is taken from the UKMT Mathematical Challenges.

You can find more short problems, arranged by curriculum topic, in our short problems collection.

You may also like