Larsen ran his first 5K race in 12 2/3 minutes. His friend Sara ran it in 9 1/2 minutes. How long did it take them altogether?

12 2/3 is also equal to 12 4/6 and 9 1/2 is equal to 9 3/6 so 12 4/6 +9 3/6 and your answer is 22 1/6

38+105= 143, 39+104=143, and you will find then adding the numbers on opposite sides, moving inwards yields the answer 138 every time. because of this, you’re going to multiply 138 times the number of pairs, which is 34. therefore, 34*138= 4692(i’m sorry if it’s the wrong numbers, but it’s the right concept)