5 is a Prime number - you can't split it up into a product of smaller integers. However, you can choose any number (except zero), then divide 5 by that number to get another number which, when multiplied together, give you zero.
The answer to the question of what can you multiply to 5 to get 9 is 4.
125
Multiply 80 by 1.05 to increase by 5%.
To find the number that you can multiply by 5 to get 22, you would divide 22 by 5. This calculation results in 4.4. Therefore, you can multiply 5 by 4.4 to get 22.
You don't multiply by the second number, you multiply by the recipricol. For example, 5/8 divided by 3/5... you multiply 5/8 by 5/3. Which would give you 25/24ths, or 1 and 1/24.
You multiply 20 by 5 to get 100
1 x 5
1 and -5
1 and -5
25
if you multiply an even number by 5 then it will always end in 0 but if you multiply an odd number by 5 then it will always end in 5.
the reverse would be to divide by 5 or the inverse would be to multiply by 1/5 (both answers are mathematically the same)