Math Antics - Decimal Arithmetic

Why do we line up the decimals?

• to keep the work organized

• to line up the tens place with the one's place

• to line up the tenths place with the hundredths place

• to line up and separate the ones place from the tenths place.

Since he POINTS, and we don't, what are the correct ways to read the two decimals 10.8 and 5.34?

• Ten and eight hundreths and five and thirty-four tenths

• Ten and eight tenths and five and thirty-four thousandths.

• Ten and eight tenths and five and thirty-four hundredths.

Which column will he start adding in?

• tens

• ones

• tenths

• hundredths

What does he still need to do?

125.2 + 39.99=

20.59 + 1.321=

25.99 + 0.82 + 145=

Why does the order matter?

• It doesn't matter, either way, you will get the same answer.

• It does matter because there is no commutative property of subraction.

673.44 - 58.2 =?

15 - 5.82 =?