Question

the sum of the prime numbers less than 8 is equal to 17 .find the sum of the prime numbers less than 21​

Answer 1

Prime numbers: 2 ,3 , 5 , 7 ,11 , 13, 17, 19, 21, 23, ....

Under 21: 2, 3, 5, 7, 11, 13, 17 and 19

2 + 3 + 5 + 7 + 11 + 13 + 17 + 19

5 + 12 + 24 + 36

17 + 60 = 77

The resultado is 77

I hope this helps!❤