what #s will go into 7 and 45

Question

I need it for school and i fave no clue i need lots of help

Answer 1

7 is a prime number. The only factors of 7 are 1 and 7.

45 is not a prime number - since it ends in a 5, that is a hint --- 5 goes into 45. The factors of 1 are found by just listing the numbers and seeing if the number goes in --

45:

1 - yes, 1 x 45

2-no

3 - yes, 3 x 15

4 - no

5 - yes, 5 x 9

6 - no

7 - no

8 - no

9 - it is already on my list (5 x 9 = 45), so my list is done.

Looking at the list - there is only 1 number on both lists....

Knowing the divisibility rules helps so much in factoring, and in math in general. Google them - they are not complicated and they really make math easier! Also being able to recognizer the prime numbers up to at least 40 is a good idea. I never memorized a list - I stink at memorization. Knowing the divisibility rules helps you quickly determine if a number is prime.