What is the greatest common factor of 63 and 21

21

Step-by-step explanation: To find the greatest common factor for the numbers 21 and 63, make a factor tree for each of the numbers.

21 is 3 × 7.

63 is 3 × 21 and 21 is 3 × 7.

The greatest common factor therefore is 3 × 7 or 21.

just find the gcf and solve the gcf's until you get each answer i have a really good feeling somethings missing xd (like the dimensions of the fence) *cough *cough *hint *hint

step-by-step explanation:

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons