How do you add fractions?

To add fractions, find the LCD (Least Common Denominator) or any common denominator of the fractions. For example, if you wanted to add 1/3+2/7, you find the LCD, which is 21, because 3x7=21, and 3 and 7 are both prime numbers. Now each fraction will have denominators of 21, so we will get 7/21+6/21. To add them together, add the numerators to get 13/21. Find the least common denominator of two fractions and then add the numerators. Hope it helps!

Step-by-step explanation:

answer: all of the odd numbers were opened

the first person was the one that was opening all of the lockers. since one is odd, this causes all of the odd number lockers to be opened in the end.