Thomas R. answered • 05/30/18
Tutor
4.9
(2,020)
A.S. in math &experienced with SAT, GED, and other standardized tests
Okay, deep breath and here we go! The easiest method for my students to understand is usually the factor tree, in which you keep reducing the question to pairs of factors. Anything that doesn't is circled as a prime and left alone until the end. Since I can't circle thing in this editor, I will bold primes when they appear.
140
|
--------|-------
10 14
| |
----------- -------------
| | | |
2 5 2 7
Note: primes don't have to suddenly appear on the same row. If I had chosen to keep dividing by 2 instead, the entire left side would be primes and the right would have stayed composites until the end.
The solution is, initially: 2 * 5 * 2 * 7
In the index form, though, it is written:
2² * 5 * 7
