Question 299971
There are 100 possible combinations of two card draws. 
1 1
1 2
1 3
1 4
.
.
.
10 7
10 8
10 9 
10 10
Only 9 of them sum to 10.
1+9=10
2+8=10
.
.
.
9+1=10
So the probability is 9/100.