by mathbuddy » Fri Jul 22, 2011 3:51 pm
To find the common denominator of 7/8 and 9/10, write some multiples of 8 and 10 as shown below:
8 = 8, 16, 24, 32, 40, 48.........(most often we need to write first 5 or 6 multiples)
10 = 10, 20, 30, 40................(Once you find the common multiple stop there, in this case we got 40)
Hence, the common denominator is 40 for 7/8 and 9/10.