First, 5/3 = 1.6
21 x 1.6 = 34.99999999
But, when I put it in a calculator, the 1.6 was repeated so:
Round 34.99999999 to 35
35 books
3cd^2(6cd + 14cd^2)
18cd^3 + 42cd^4
10 times (3*4)
You have to multiply 10 with both of the numbers in parenthesis
So, 10*3=30 and 10*4=40
30+40=70
Does this look right for the first one