1.7 Adding and Subtracting Decimals Miss McKeown

Aim: How can we add and subtract decimals and solve problems involving decimals? Do Now: Skills you’ll need! 1. _____is a method of estimation that compares a digits value to 5. 2. Round each number to the underlined place. 72 149 108 3,196

McDonald’s Menu $2.99 $4.18 $2 $3.29 $4.28 $1.09 $1.59 $1.49

Zeros after the decimal point Explain why the decimals 0.2, 0.20, and 0.200 are equivalent decimals.

How do we add decimals? 43.2 + 2.1 = 45.3 What’s the rule? Have students come up with the rule Challenge with another example with one addend with one decimal place and the other with two.

Find the value 2 ½ + 2 ¾ =

Add and subtract using Front-end estimation 1. Estimate the total cost of buying one of every size of popcorn shown at the left 2. 3.026 + 14.7 + 1.38 3. 0.84 + 2.0 + 3.32 Small :$3.98 Medium $6.48 Large: $9.08 Junior $3.47 Front End Estimation is when you add the whole numbers first and estimate the value of the decimals after 1. 3+6+9+3 -- .98+.48+.08+.47~$2+21~$23 2. 3+14+1 = 18 -- .026+.7+.38~1.1 + 18 ~19.1 3. 5 – 6.1

Shopping Time! Find the total cost of this food: 5 lb. chicken at $2.99 per pound, 3 dozen eggs at $2.35 per a dozen, 4 Liters of Coke at $0.99 per Liter, and 3 bags of chips at $2.79 per bag. 34.33

Word Problems Gasoline prices are given to the nearest thousandth of a dollar. If a gallon of gasoline costs $3.499 and increases $0.09, what is the price of gasoline after the increase? 3.589

Kayla placed 4 weights on a scale during science class Kayla placed 4 weights on a scale during science class. If each weight weighed 0.2 grams, what did the scale read? Daniel's dog eats 0.4 kilograms of dog food each day. How much dog food will Daniel's dog eat in 2 days? .8

Matching Game 0.4 0.4 + 0.5 0.6 0.4+0.3 0.3+ 0.3 41.30 2.24 1.02+2.02 121.1 +124.4 0.9 3.04 .007 0.7 245.5 .004+.003 63.52 22.22 .024 2.20 + .04 .004+.020

STUDENT TIME  PARNTER WORK : PAGE 204 INDEPENDENT WORKBOOOK PAGE 203 HOMEWORK : WORKSHEET

Aim: How can we add and subtract decimals? Do Now: Find the perimeter of the rectangle 5.4 cm 2.34 cm Challenge: Find the area of the figure

2 ¾ -2 ½ =

Mrs. Karpuzi’s store $1,000.00 shopping spree

Evaluate the following.. 60 – 43.6 18.31 – 8.25 38.61 – 5.04 88.39 – 20.8 75 – 14.25

EXIT TICKET Jabir buys 2.74 pounds of dried pinto beans and 4.05 pounds of dried lima beans. What is the difference between the weights of the beans that Jabir buys? Kelly’s baby brother weighs 7.71 pounds. Her newborn kitten weighs 0.24 pound. How much more does Kelly’s baby brother weigh than her kitten? DON’T FORGET TO RATE YOURSELVES! 1 2 3 4