Answer :
10 girls are not on either team
first subtract 6 from 8 to get 2 (since it's easier) because those 6 girls are on the math league team as well
next add 2 and 13 to get 15
last subtract 15 from 25 to get 10
first subtract 6 from 8 to get 2 (since it's easier) because those 6 girls are on the math league team as well
next add 2 and 13 to get 15
last subtract 15 from 25 to get 10