Find least common multiple of 8 and 10.
The answer is 40.
7/8=x/40. We had to multiply 8 by 5 to get 40.
Whatever you do to denominator you must do to numerator. Multiply 7 and 5 to get 35.
Now we have 7/8 is equal to 35/40.
Next, for the 9/10 part. We multiplied 10 and 4 to get 40 so multiply the numerator by 4 as well and you get 36.
Now we have 9/10 is equal to 36/40
The problem is now 35/40 and 36/40
35/40 < 36/40
Which is the same as
7/8 < 9/10