I can make reasonable estimates to a situation using whole numbers and fractions. Rachel A. Darnell

Essential Questions What is estimation? When should you use estimation? Why would you estimate mentally before writing down your computations? How would that help you better understand the problem? What does it mean to be reasonable?

Let’s first practice deciding when an estimate is reasonable. Reasonable means that the “guess” is logical and makes sense. Is this reasonable? I need to be at Acacia by 7:30 AM and my house is 12 miles away. So, I should leave my house by _________. 7:308:306:007:00 I want to buy a blouse that cost $12.99 so I need to take _________ into the store. $12.99$12.00$13.00$15.00 So the items marked with an X are unreasonable

Mr. Hernandez, one of the fourth grade teachers, is very grouchy today. He said gas for his car costs too much. This morning he paid $1.96 per gallon for gas. If he put 9 gallons of gas in his car, how much did he have to pay? Step 1 - Round the price of gas to the nearest dollar $2.00 Step 2 - Decide on an operation multiply Step 3 - Do the computation Step 4 - Multiply using the real numbers. Step 5 - Compare your real answer with the estimate and decide if it is reasonable. 9 X $2.00 = $18.00 $1.96 X 9 = $17.64

Sydney has twenty dollars to spend at the mall. He bought a CD for $12.95 and a t-shirt for $7.95. Does he have enough money. Step 1 - Round the price of the CD and t-shirt to the $13.00 and $8.00 Step 2 –Decide on the operation…. Add??? Why? Step 3 - Do the computation Step 4 - Add using the real numbers. Step 5 - Compare your real answer with the estimate and decide if it is reasonable. Yes, it is REASONABLE!!! $ $8.00 = $21.00 $ $7.95 = $20.90

Eleven years ago thousands of bright yellow rubber ducks and other rubber animals accidentally were spilled from a tanker into the sea. An oceanographer has been studying ocean currents by watching the travels of the little rubber animals. A few of them have shown up on beaches on the east coast of the United States. The company that made them will give a reward to anyone who finds one of the ducks. If the reward is $88 per duck and Nathan finds five of them, how much will his reward be? Estimate the answer following the five steps.

Step 1 - Round the amount of the reward to the nearest dollar Step 2 - Decide on an operation..… Step 3 - Do the computation Step 4 - Multiply using the real numbers. Step 5 - Compare your real answer with the estimate and decide if it is reasonable. multiplication $90.00 Yes, it is REASONABLE!!! $90.00 X 5 = $ $88.00 X 5 = $440.00

Hunter drew a picture of the Santa Maria, the Pinta, and the Nina. His teacher told him it was very good, so he entered it in the school art contest. His picture won first prize. The first prize was three times more than the amount of money won for second prize. If second prize was $19.00, how much did Hunter win? Step 1 - Round the amount of the reward to the nearest dollar Step 2 - Decide on an operation Step 3 - Do the computation Step 4 - Multiply using the real numbers. Step 5 - Compare your real answer with the estimate and decide if it is reasonable. $20.00 multiplication REASONABLE $20.00 X 3 = $60.00 $19.00 X 3 = $57.00

Madison gave away about 756 pieces of candy on Halloween. She gave four pieces of candy to each child. About how many children visited her house? Step 1 - Round the amount of the cant to the nearest ten Step 2 - Decide on an operation Step 3 - Do the computation Step 4 - Divide using the real numbers. Step 5 - Compare your real answer with the estimate and decide if it is reasonable. 760 division REASONABLE 760 ÷ 4 = ÷ 4 = 189

Remember you estimate should always be __________________ REASONABLE