Focus: How to use rounding to estimate products

Review Rules of ROUNDING: Round each number to the place value that is underlined: ,098 4,456 $46.00 $84.00 $ $ $2, $4, ,100 4,500 $50.00 $80.00 $ $ $2, $4,500.00

Turn & Talk: How do we use rounding to help us ESTIMATE a product? $398 x 18 = $400 x 20 = $400 x 20 = 8 $8,000 $398 x 99 = $400 x 100 = $400 x 100 = 4 $40,000 Did we round the numbers UP or DOWN? UP. Therefore the actual amount would be? LESS than the estimate. $7,164 $39,402

How do we use rounding to help us ESTIMATE a product? $54 x 73 = $50 x 70 = $50 x 70 = 35 $3,500 $202 x 32 = $200 x 30 = $200 x 30 = 6 $6,000 Did we round the numbers UP or DOWN? DOWN. Therefore the actual amount would be? MORE than the estimate. $3,942 $6,464

Let’s go shopping and use rounding to help us ESTIMATE products!

Peter buys 28 boxes to store his collector baseballs. Each box holds 36 balls. About how many baseballs can he store? 28 boxes x 36 balls (each) = 30 x 40 = 30 x 40 = 12 1,200 baseballs What pieces of information are needed to find the product?

Alex buys 12 video games at FYE for his new Wii2. Each game is on sale for $ About how much did he spend on video games? 12 games x $29.95 each = 10 x $30 = 10 x 30 = 3 $300 What pieces of information are needed to find the product?

Jayna finds Peanut Butter & Jelly Ts- on sale for $19.95 each. She buys 11 shirts to give away for the holidays. About how much did she spend on all of the shirts? 11 shirts x $19.95 each = 10 x $20 = 10 x 20 = 2 $200 What pieces of information are needed to find the product?

Amanda’s soccer coach asked her to pick up field cones for the season. She bought 29 boxes each for $8.95. About how much did her coach reimburse her? 29 boxes x $8.95 each = 30 x $9 = 30 x 9 = 27 $270 What pieces of information are needed to find the product?

Brendon wants to purchase a new set of drawing pencils. He buys 6 sets. Each set contains 38 pencils. About how many pencils did he buy? 6 sets x 38 pencils per set = 6 x 40 = 6 x 40 = What pieces of information are needed to find the product?

Michael buys a set of 3 Star Wars mini-figures. Each set sell for $16.95 in the store. How much did he spend on all of them? 3 figures x $16.95 each = 3 x $17 = What pieces of information are needed to find the product? X X

Are you ready to go around the room?

Center 1Center 2Center 3 Center 4Center 5Center 6 Alyssa L. went to Blockbuster to rent some movies for a rainy weekend. She chose 6 movies. Each movie rental cost $3.99. About how much did she spend renting movies? Samantha and her brother wanted to buy some new games. They found 32 new games at FYE. Each game cost $8.97. About how much did they spend on the games purchased? Emily was going to have a party. She wanted to order 9 pizzas from Giove’s Pizza Kitchen. Each pizza cost $8.76. About how much did Emily spend on pizzas for the party? Louisa and Tamara were making bead necklaces for their friends. It took 57 beads to make each necklace. They wanted to make 8 necklaces. About how many beads would they need to complete the job? Daniel and Nicolas had a lemonade stand. They charged people $2.25 for a lemonade/cookie combo. If they sold 29 lemonade/cookie combos, about how much money did they earn in all? David and Johnny were raking leaves to earn extra money. Each yard they raked they charged $ If they raked 12 yards about how much money did they earn?

Center 7Center 8Center 9 Center 10Center 11Center 12 Amber was counting her Halloween candy and saw that she had collected 289 pieces. If each piece weighed about 3.2 ounces about how much did all of Amber’s candy weigh? Salma wanted to count all the seeds in her 9 pumpkins. If each pumpkin had 72 seeds, about how many seeds did they have in all? J.D. and his family bought a new puppy. They went to the store and bought 9 packs of dog treats. If each pack cost $23.45, about how much did his family spend? Caylie went to a cheerleading competition. There were 43 teams competing. If each performed for 3.32 seconds, about how long did the competition last? Nicolas needed gas for his lawn mower. He went to Exxon and bought 11 gallons of gasoline. Each gallon cost $3.999 per gallon. About how much did Nicolas spend on gas? Johnny was measuring the height of 89 trees. If each tree was 43.4 inches tall about how tall were they altogether?

Center 13Center 14Center 15 Center 16 Peter was making apple cider for his class. If he makes 8.9 ounces for 26 students, about how many ounces does he need to make? Alyssa C. was taking herself and 8 friends to Sunny Daes Ice Cream Shop. If she bought herself and EACH friend an ice cream that costs $4.75 each, about how much did she spend in all? Tamara was making coffee at Dunkin Donuts. She put 8.9 ounces of water in each coffee pot. If she fills 21 coffee pots about how much water will she need? Mrs. Russo went to eat at Marissa’s Restaurant. She ordered three appetizers that each cost $8.65. If she also left a TWO dollar tip, about how much did she spend??