60
the answer to 20 + 20 = 40
the sum for 20 + 40 + 70 + 80 = 210
20 of them
The sum of the first 20 even numbers... is 110
-- Drop 20 pennies or little stones onto a small patch of bare ground. -- Drop 40 more pennies or little stones onto the same place. Do it carefully, so that you don't scatter them. -- Pick up all of the pennies or little stones and count them. The number you have is the sum of 20 and 40.
It is: 20+20 = 40
the answer to 20 + 20 = 40
the sum for 20 + 40 + 70 + 80 = 210
20+20=40 20x20=400
The sum of two numbers between 20-40 is 58. The difference is 12
20.
440
20 and 20.
2,4,8,10 and 16 are factors of 400.
20 of them
The sum is: 23+29+31+37 = 120
40, the sum of the protons and neutrons.