To multiply powers of the same base, add their exponents. To divide powers of the same base, subtract the exponent of the divisor from the exponent of the dividend. Enter the number and it will tell you all the possible questions that would give the number as an answer. We can see by subtracting 206 from 814 that the increase in the number of apples is 608. Remember we started with 206, not zero.
Percentages are fractions.
This is the step many people miss. So, 3.951 minus 1 equals 2.951. Now let's do an accurate check of our original problem. Integral table is awsome. This is some of the best money I have ever spent.