What is 1/5 plus 3/7 estimate?

32/35 is the answer. You will need to find the least common denominator, which is 35. To change the denominator of 1/5 into 35, you must multiply both numerator and denominator by 7, which will give you 7/35. Then you must change the denominator of 3/7 to 35 as well by multiplying the top and bottom by 5, which will give you 15/35. Then you add 7/35 and 15/35 together which should give you 32/35.