Math Mystery

Greater than or Less than Compare whole #’s first If the same – compare the # after the decimal (tenths place) Then move to the hundredths If needed – add 0’s to make #’s have the same amount of digits, then compare 1.2201 > 1.2100 7.001 < 7.01

Powers of 10 Rule Multiply = move decimal to the RIGHT the same # of places as the # of zeros EX: 6.589 X 10 EX: 6.589 X 10 = Answer: 65.89 1 zero  1 time

Powers of 10 Rule Divide = move decimal to the LEFT the same # of places as the # of zeros EX: 6.589 X 1000 EX: 6.589 X 1000 = Answer: 0.006589 3 zeros  3 times

2 4 6 . 8 5 1 Place Value Decimal Point Thousandths Hundredths Thousands Hundreds Tens Ones Decimal Point Tenths Hundredths Thousandths 2 4 6 . 8 5 1

Addition/Subtraction Decimals Line up the decimals Fill in spaces with 0’s Add or subtract Bring down the decimal 5.94 + 2.10 8.04 15.90 - 04.15 11.75

Multiplying Decimals Put the # with the most digits on top Multiply like normal Count #’s behind decimal Count same amount from the right in the answer and place the decimal 5.94 2 digits behind X 2.1 1 digit behind 12.474 --- 3 digits from right

Dividing Decimals Make divisor whole # by moving decimal Do the same in the dividend Bring decimal straight up Divide .2 ÷ 3.48  2 ÷ 34.8 ≈ 0.057  