Multiplying Decimals How does multiplying decimals compare to multiplying whole numbers?

Launch Activity Kevin walked his dog for 2.5 hours, walking at a speed of 3.2 miles per hour. How far did he walk? Hint: Distance = speed x time

Multiply 25 x 32. In your group, discuss your answer. How would the answer change if the problem was now 2.5 x 3.2? Would the digits in the answer still be the same? What would change?

Using Estimation If we round 2.5 and 3.2 to the nearest whole number, that will help us determine where the decimal point should go. 3 x 3 = 9high estimate Answer has to be less than 9. Where should the decimal point go?

Multiplying Decimal Algorthim Can you come up with a rule for multiplying with decimals?

Steps to Multiplying Decimals Multiply as you would with whole numbers. Count the number of decimal places in each decimal factor. The product has the same number of decimal places. The decimal points points do not have to be aligned.

Practice Examples – Use estimation to determine if your answer is reasonable. Multiply 4.18 x 7.2 = Multiply 0.7 x 0.9 = Multiply 3.1 x 0.5 =

Pear Deck Practice Get out your iPAD and go to peardeck.com/join

Conclusion/Summary How does multiplying decimals compare to multiplying whole numbers? Add in questions on the left side of your notes.