Xiaoming plays a coin toss game. The rule is: throw a coin, then go forward 15 steps when it falls, and go back 15 steps when its back is up. Xiaoming tossed a coin 10 times, and as a result, he walked 100 steps before. How many times do coins face up? What about backup?

back:( 15× 10- 100)÷25

=50÷25

=2 (times)

Front: 10-2=8 (times)

A: Coins face up 8 times and face up 2 times.