Me to 2 yr old daughter: Please take your finger out of your nose.
2 yr old daughter complies.
2 yr old daughter inserts a finger from the other hand into her nose.
Me: Please take that finger out of your nose too.
Daughter sticks a 3rd finger into the other nostril.
Me: That finger too.
And on. And on. There are ten fingers, two nostrils. You do the math.