{Decimal Rules

7th Grade

Today we are going to work with decimals. In your journal (notes) write anything you know about working with decimals! I want to know what you know. Use your own words, and don’t worry about using “proper math speak”! Comparing and ordering decimals? How do you add and subtract decimals? What do you know about multiplying

decimals? How do you divide using decimals?

Howdy Party People!!

2.378, 2.078, 2.387, 2.783, 2.037

Order these Decimals From Greatest to Least

Adding Decimals

780.14

478.2

Make sure that you line up your place values and add zeros where appropriate and then use regular addition rules to evaluate the expressions.

17.258

Subtracting Decimals

780.14

478.42

Make sure that you line up your place values and add zeros where appropriate and then use regular subtraction rules to evaluate the expressions.

27.698

Multiplying Decimals Use your regular

multiplication rules, and multiply the numbers. After you are finished multiplying, add the total number of decimal places that the factors hold, and move that many places to the left in your final answer

488.33

29120

4368

3.2

56.14

Dividing Decimals To divide, make sure that

your denominator (outside number) is a whole number. If it isn’t, multiply it by 10 until it is a whole number. REMEMBER, WHAT YOU DO TO ONE NUMBER MUST BE DONE TO THE OTHER NUMBER IN THE PROBLEM. Next place the decimal right above where the decimal is in the new division problem. Follow regular division rules.

0

10

01

53

72.060.35

360.5.

Practice

How much does three pounds of grapes cost if they are $1.19 a pound?

Ms. Compton’s car holds 15 gallons of gas. If she is able to drive 274.5 miles on the tank of gas, how many miles does she get to the gallon?

Elizabeth and four friends went to dinner. The total bill not including tax was $57.16, Elizabeth paid 25% of the bill and her friends split the rest equally. How much did Elizabeth pay? How much did the rest of her friends pay?

Practice