The mass of Hinto's math book is 4415 grams. What is the mass of 4 math books in kilograms?

For this problem since one kilogram is equal to 1,000 grams and there's for math books it would be 4,000 times 4,415 which is equal to 17,660,000.

17,660 because 4x4=16 and 16+1=17 and 4000x4=16,000 so add 1,600 to 16,000 because 4x4 again =16 and 4x10=40 and 4x5=20 so add them all up and it equals 17,660