Step 1: Circle the place value of the digit to be rounded. This is the rounding digit. Step 2: Look to the neighboring digit on the right. Step 3: a) If the neighboring digit is less than five (0 - 4), keep the rounding digit the same.
The greatest common multiple is 8m, so this means that you can factor it out to:
=8m(3n+4)
=(8m•3n)+(8m•4)
=(24mn)+(32m)
=24mn+32m
The answer is option 2.