Assuming LCD means Lowest Common Denominator Assuming by "and" you mean adding the two
Well, you go by the multiples of 7; 7, 14, 21, 28, 35, 42, 49, 56, 63,<u> 70</u> Multiples of 10; 10, 20, 30, 40, 50, 60, <u>70</u>, 80, 90, 100 Straight away you can see the lowest common multiple is 70, Now to go about adding them, 2/7 * 10 (both sides) , 20/70 9/10 * 7 (both sides) , 63/70
Then you add the two; 20/70 + 63/70 - now we can add them because they share the same denominator 20/70 + 63/70 = 83/70 = 1 whole 13/70 (simplified)
<u>The LCD is 70
Quick tip, </u>to find a common multiple (not necessarily the lowest) multiply the two denominators.
The least common denominator or LCD is 70 because for 10=10,20,30,40,50,60,70,80 7=7,14,21,28,35,42,49,56,63,70,77 and 70 is the least common denominator of 10 and 7 so 70 ims your answer
