Ok so this question is about scientific notation. Which isn’t hard. But the numbers given are too much for a calculator. I don’t get how to do it. Please help and please provide an explanation

Write two subtraction equations that are equivalent to 5 + 12 = 17.

Write 17/20 as a decimal and as a percent.

Dexter read 11 science fiction books and 5 history books. lena read 9 science fiction books and 4 history books. compare the students’ ratios of science fiction books to history books. 1. determine the ratios’ form:    science fiction books to history books 2. write the ratios as fractions:    dexter: 115; lena: 94 3. rewrite with a common denominator. 4. compare. 5. answer the question. determine which shows the correct comparison of the ratios for this problem.