Express the fractions 3/4 7/16 and 5/8 with the lcd

LCD means Least Common Denominator. To find the LCD of 3/4, 7/16, & 5/8, we will first get the multiple of each denominator until we get the same multiple of the three denominator
Multiple of
     i. 4 are 4, 8, 12, 16
     ii. 16 are 16
     iii. 8 are 8, 16

16 is the multiple of 4, 16 and 8. So we will use it now as the LCD of the three given fractions.
We can now express the given fractions with the LCD
     3/4 = 12/16
     7/16 = 7/16
       5/8 = 10/16