# Bits and Pieces III: Inv. 1.3 Using Fractions to Add and Subtract Decimals.

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Bits and Pieces III: Inv. 1.3 Using Fractions to Add and Subtract Decimals

Getting Ready for Problem 1.3 Remember that Sally Jane and her friend Zeke went to Quick Shop to buy snacks. They picked out a bag of pretzels for \$0.89 and a half-gallon of cider for \$1.97.

Getting Ready for Problem 1.3 How is this like thinking of the cost in pennies and then finally writing the sum in dollars?

Getting Ready for Problem 1.3 The top number in the fraction is the number of pennies. When you divide that number by 100 you get the dollars which is the whole number and the left over decimal, which is the number of pennies.

Problem 1.3- Using Fractions to Add and Subtract Decimals Write the decimal numbers in parts (1) to (4) in fraction form with denominators of 10, 100, 1000, etc. Then add or subtract the fractions. Write a number sentence in fraction notation that shows your computation. Create a table much the like from yesterday but instead of decimal notation put fraction notation.

Problem 1.3 Using Fractions to Add and Subtract Decimals Carmela signed up to clean 1.5 miles for the cross- country team. It starts to rain after she has cleaned 0.25 of a mile. How much does she have left to clean? Person Number Sentence (decimal notation) Carmela1.5 -0.25 =1.25 miles

Problem 1.3 Using Fractions to Add and Subtract Decimals

Pam cleans 0.25 of a mile for the chorus and cleans another 0.375 of a mile for the math club. How much does she clean altogether? Person Number Sentence (decimal notation) Carmela1.5 -0.25 =1.25 miles Pam0.25 + 0.375= 0.625 miles

Problem 1.3 Using Fractions to Add and Subtract Decimals How do you know a fraction for 0.375?

Problem 1.3 Using Fractions to Add and Subtract Decimals You look at place value, specifically where the 5 is. The five is in the thousandths place thus 375/1000.

Problem 1.3 Using Fractions to Add and Subtract Decimals

You must have common denominators. Why do you need common denominators?

Problem 1.3 Using Fractions to Add and Subtract Decimals

How did you change 25/100 to 250/1000?

Problem 1.3 Using Fractions to Add and Subtract Decimals You multiplied 25/100 x 10/10 =250/1000, in decimal notation you had 0.25 and you put a zero at the end to make 0.250. 0.25 and 0.250 are equal.

Problem 1.3 Using Fractions to Add and Subtract Decimals Jim, a member of the chess club, first cleans 0.287 of a mile. He later cleans another 0.02 of a mile. How much of a mile does he clean altogether? Person Number Sentence (decimal notation Carmela1.5 -0.25 =1.25 miles Pam0.25 + 0.375= 0.625 miles Jim0.287 + 0.02= 0.307 miles

Problem 1.3 Using Fractions to Add and Subtract Decimals

Teri doesn't notice that she finished her section of highway until she is 0.005 of a mile past her goal of 0.85. Person Number Sentence (decimal notation) Carmela1.5 -0.25 =1.25 miles Pam0.25 + 0.375= 0.625 miles Jim0.287 + 0.02= 0.307 miles Teri0.85 + 0.005= 0.855 miles

Problem 1.3 Using Fractions to Add and Subtract Decimals