A hundredth part

Learn what a hundredth is, and when you need parts even smaller than tenths.

Sometimes tenths are still too rough. Zoom in on one tenth and split it into 10 equal parts. Each tiny part is one-hundredth.

10 hundredths = 1 tenth
100 hundredths = 1 whole

Adding works just like before, with one more column. 15 and 3/10 4/100 + 2 and 6/10 8/100: wholes 15 + 2 = 17; tenths and hundredths together 34/100 + 68/100 = 102/100 = 1 whole and 2 hundredths. Total: 18 and 2/100.

Or change everything to hundredths: 1534/100 + 268/100 = 1802/100 = 18 and 2/100. Same answer.

It's exactly how you add whole numbers. 483 + 268 = (400 + 80 + 3) + (200 + 60 + 8) = 600 + 140 + 11 = 751. Each column spills over into the next, just as 102 hundredths spilled over into a whole.

Subtraction borrows the same way.

25 and 9/10 − 6 and 4/10 7/100: no hundredths to take 7 from, so borrow a tenth as 10 hundredths: 25 and 8/10 10/100. Then subtract: 19 and 4/10 3/100.
Sometimes you borrow twice: 15 and 3/10 4/100 − 2 and 6/10 8/100 → 14 and 12/10 14/100 − 2 and 6/10 8/100 = 12 and 6/10 6/100. (653 − 268 borrows the same way.)

Splitting a tenth into ten gives hundredths; adding and subtracting them carries and borrows just as whole numbers do.

Splitting a tenth into ten gives hundredths.

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