You sometimes need to rewrite a factor because the lead number is not between 1 and 10 as it needs to be in scientific notation. For instance, if we had lead numbers of 2 and 5, as we do in the following problem.
2x10^3 * 5x10^9
Then we get the answer of 10x10^12. We need to adjust this by moving the decimal place and increasing the exponent by 1. The correct answer would be 1x10^13 instead.
If we have 156 beads and we can make one bracelet with 9 beads we divide 156 by 9 and get 17 1/3. since we cannot have 1/3 of a bracelet, we can make 17 bracelets.
first divide 90 by 4 to see how many words per minute
90 ÷ 4 = 22.5
then multiply 22.5 by 10 to get your answer
so your answer is;
225 words per 10 minutes
