Type P - help

[i-qah]

This one is from the IPS VR Additional Practice Questions (C).

Type P - Q11

1, 1, 2, 6, 24, (120)

Neither my son or 1 could work out why it's 120?

[Guest]

Multiply the first number by 1, the second number by 2, the third by 3, the fourth by 4 and the fifth by 5.

So 1x1=1
1x2=2
2x3=6
6x4=24
24x5=120

[i-qah]

We'd been stuck on that all night. It's obvious now, thank you Guest!