What is 6.64 divided by 0.4

Find the number of positive three-digit even integers whose digits are among 9, 8, 7,5, 3, and 1.

In an improper fraction, is the numerator equal to, less than, or greater than the denominator

Abicycle training wheel has a radius of 3 inches. the bicycle wheel has a radius of 10 inches.approximately how much smaller, in square inches and rounded to the nearest hundredth, is the area of the training wheel than the area of the regular wheel? *