Reteach. Teacher Edition. Chapter 9. Grade 4

Transcription

1 Reteach Teacher Edition Chapter 9 Grade

2 Lesson Reteach Add Like Fractions Remember that to add like fractions, you find the sum of the numerators, but keep the denominator the same. Find _ 1 + _ 1. Use a number line _ = _. Simplify the fraction: _ = 1 _ Find each sum. Write in simplest form _ = _ _ 6 = _ 8 + _ 8 = 1 + Grade Chapter 9 Operations with Fractions 7

3 Lesson Reteach Subtract Like Fractions To subtract like fractions, find the difference between the numerators, but keep the denominator the same. Find _ - 1 _. _ Take away 1 _. The difference is _. So, _ - 1 _ = 1 _. Write the answer in simplest form: _ = _ 1 Find each difference. Write in simplest form. _ 6 1. _ 6 - _ 1 6 = Simplify: _ 6 = _. _ _ 8 = Simplify: _ _ 9 - _ = Simplify: _ _ 6_. _ _ 9 = Simplify: _ 9 9 _. _ 8 - _ 8 = Simplify: _ 8 8 = = = = 7 Grade Chapter 9 Operations with Fractions

4 Lesson Reteach Problem Solving: Work Backward Ms. Alvarez went to the movie theater. She bought a bottle of water, a box of popcorn, and a ticket. She spent _ 1 of her money on popcorn and _ of her money on the ticket. What fraction of her money did she spend on the bottle of water? Step 1 Understand What facts do you know? Ms. Alvarez bought water, popcorn, and a ticket. Ms. Alvarez spent _ 1 of her money on popcorn. Ms. Alvarez spent _ of her money on a ticket. What do you need to find? What fraction of her money did she spend on the bottle of water? Step Plan Make a plan. I will start with the total amount Ms. Alvarez spent and work backward to find the amount she spent on water. Step Solve Step Check Carry out your plan. You know that Ms. Alvarez spent _ of her money on the ticket. Take away _ from one whole. 1 = - You know that Ms. Alvarez spent _ 1 of her money for popcorn. Subtract _ 1 from _. _ - _ 1 _ 1 So, Ms. Alvarez spent _ 1 of her money on a bottle of water. Make sure your answer is reasonable. You can use addition to check your answer. + _ + _ 1 _ or 1 whole So, the answer is reasonable. Grade Chapter 9 Operations with Fractions 7

5 Lesson Reteach Solve each problem by working backward. Problem Solving: Work Backward (continued) 1. Kim has three kinds of state quarters. Some of them are Georgia quarters. South Dakota quarters make up _ 1 of her collection. New York quarters make up _ of her collection. What fraction of Kim s collection are the Georgia quarters?. Andrew worked on his painting Monday, Tuesday, and Wednesday. Tuesday he painted for _ 1 of an hour, and Wednesday he painted for _ of an hour. So far, Andrew has painted a total of 1 hour. What fraction of an hour did Andrew paint on Monday? of the quarters an hour. Stefan spent _ 1 of his money on a ticket to the baseball game. He then spent $ on a hot dog and a soda. He has $ in his wallet now. How much money did Stefan start with? $16. Kenji jogged around the block _ 1 times. The rectangular block has a length of yards and width of 90 yards. How many yards did he jog in all? 1,00 yards. Joan hiked the Lonesome Lake Trail, which took hours 1 minutes. The it took hours 0 minutes to hike the Greenleaf Trail. She finished hiking at :1 P.M. What time did she begin? :0 A.M. 76 Grade Chapter 9 Operations with Fractions

6 Lesson 6 Reteach Add Mixed Numbers Find 1 _ + _. Step 1 Add the whole numbers. 1 + = Step Add the fractions. _ + _ = _ Simplify. 1 1 _ Step Add the sums. + 1 _ 1 = _ 1 So, 1 _ + _ = 1 _. Find each sum. Write in simplest form. 1. _ + 1 _ =. _ + _. 1 _ 6 + _ 6 =. _ + _. 6 7 _ + 6 _ = _ 1 _ 6 1 _ 6 9 _ 9 _ Grade Chapter 9 Operations with Fractions 77

7 Lesson 7 Reteach Subtract Mixed Numbers Find _ - 1 _. 1 Make equivalent fractions. + _ + _ } } 1 Subtract the fractions. _ 19 - _ 7 _ 1 Simplify. _ 1 _ = 7 _ = 19 _ So, _ - 1. Find each difference. Write in simplest form. 1. _ _ =. _ 6 - _ 6 =. 6 _ - _ =. 6 _ _. 9 _ _ 8 = 1 _ 1 _ _ 8 78 Grade Chapter 9 Operations with Fractions

8 Lesson 9 Reteach Multiply Fractions by Whole Numbers Find 1 _. + _ 1 + _ 1 = _ 1 + _ 1 = 1 _ 1 Multiply. Write in simplest form. 1. _. 1 _ =. _ = 7. _ _ 1 _. _. 1 _ 8 = _ = 8. _ = 1 1 _ 1 _ Grade Chapter 9 Operations with Fractions 79