Translation of the statement "5 * a*a*c*a"

How do you summarize data in a two-way frequency table?

If 1.4% of the mass of a human body is calcium, how many kilograms of calcium are there in a 165-pound man? 1.0 kg ca 5.1 kg ca 1.0 x 102 kg ca 5.1 x 102 kg ca

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25