to find the number, you add them up and divide by 2
to add them up conver the bottom number to the same number
7/8 and 1/9
factor
8=2 times 2 times 2
9=3 times 3
least common multiplue=2 times 2 times 2 times 3 times 3=72
7/8 times 9/9=63/72
1/9 times 8/8=8/72
add them
63/72+8/72=71/72
dividee by 2
same as multiplyu 1/2
71/72 times 1/2=71/144
the number is 71/144