Math homework help -
factors, primes and
composites, prime factorization


Math homework help home

Students send me scans (or cell phone pictures) of their math homework with their own answers written down. I review and rectify mistakes, if any so that they have all correct answers by the time they turn them in to their school teachers. I also make efforts to explain the concepts/steps briefly.

Note that this is a paid service but costs significantly less than live tutoring sessions. Here are a few examples from pre algebra to show what I receive and what I send back. You can use these solutions as solved examples to learn on your own. Don't miss out on the tips and tricks, if any.


Word problems related to factors
Prime factors and exponents
Prime factorization with exponents, primes and composites
Primes and composites

 Word problems related to factors




What I received


What I sent back

click on pictures to enlarge

 Prime factors and exponents




What I received


What I sent back

click on pictures to enlarge

 Prime factorization with exponents, primes and composites




What I received


What I sent back

click on pictures to enlarge

 Primes and composites




What I received


What I sent back

click on pictures to enlarge

List of maths homework help by email is here

Tip: A quick way to figure out if 3 can divide a number without leaving a remainder is to add up all the digits in the number and check if 3 can divide the sum obtained without leaving a remainder.

For example, to check if 3 can go into 93, add 9 with 3. Since 9 + 3 = 12 and 3 can divide 12, 3 can also divide 93 without leaving a remainder.

Similarly, 3 can't divide 145 because 1+4+5 = 10 and 3 can't divide 10.

In almost the same way, if you want to quickly find out if 9 can divide a number without leaving a remainder, add up the digits in the number. If 9 can divide the sum thus obtained, then 9 can also divide the given number.

For example, to check if 9 can go into 456, do 4 + 5 + 6 = 15. Since 9 can't divide 15, it can't divide 456 either.

Note: The tricks mentioned above work only for 3 and 9. Never try to apply these rules to find out if any other number can divide a given number. For example, if you want to find out if 4 can divide 124, you don't add 1, 2 and 4. The divisibility rule for 4 is different. We can talk about that on another day.

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