Estimation Word Problems
Basics on the topic Estimation Word Problems
Learn about how to use estimation to solve word problems with Mr Squeaks and Imani!
Transcript Estimation Word Problems
Welcome to Sense or no Sense! Mr. Squeaks and Imani must decide whether the answers to the word problems are reasonable! In order to win the prize, they will need to use estimation in word problems. In word problems, estimation to check if our answers are reasonable is a useful skill. We can use estimation strategies such as rounding, using known facts and mental maths. First, read and then reread the problem to identify the important information. Then, use rounding or known facts. Next, use mental maths to find an estimate. Finally, compare the estimation to the original answer to decide whether or not it is reasonable. If the numbers are close, your maths is most likely correct. If the numbers are far apart, your maths most likely has a mistake and needs to be corrected. Here's the first question for Mr. Squeaks and Imani. Axel and Tank plan a family trip to Submersive Studios. Admission is sixtyseven pounds and ninetynine pence for adults, and fortytwo pounds and ninetynine pence for children. Four adults and two children are going. Axel says it will cost three hundred and fiftyseven pounds and ninetyfour pence altogether. Does his answer make sense or no sense? To decide whether the answer is reasonable, they will estimate. Sixtyseven pounds and ninetynine pence is rounded to seventy pounds. There are four tickets at this price. Seventy times four equals two hundred and eighty. If we change fortytwo pounds and ninetynine pence to fortyfive pounds, we can use known facts. Fortyfive times two is ninety. Two hundred and eighty plus ninety equals three hundred and seventy pounds. Three hundred and seventy pounds is close to three hundred and fiftyseven pounds and ninetyfour pence, so Axel's answer is reasonable. " Sense!" The next round is worth double and here is the question! Zuri and Freddie collected cans to recycle. Zuri collected six boxes with twentyfour cans in each. Freddie collected four boxes with thirtyseven cans in each. Freddie says he collected two hundred and ninetytwo more cans than Zuri. Does his answer make sense? "Sense!" Mr. Squeaks answered incorrectly because he rushed and didn't estimate to check his answer. Here is how estimation would have helped him. Zuri had six boxes of twentyfour cans. What number is easier to work with for known facts than twentyfour? Twentyfive. What is six times twentyfive? One hundred and fifty. Freddie had four boxes of thirtyseven cans. What number do we round thirtyseven to? Forty. What is four times forty? One hundred and sixty. The question asks how many more, so we subtract. What is one hundred and sixty minus one hundred and fifty? Ten. Freddie's answer was not reasonable because he used addition instead of subtraction. It's the final round. They must get this correct or leave emptyhanded! Nari and Gus are planning a party. They invited twentyeight guests and want to have enough for two hot dogs each. Hot dogs come in packs of twelve. Nari says they need to buy five packs. Does his answer make sense or no sense? Pause the video and solve this problem to see what they should answer and press play when you are ready for the solution! Twentyeight rounds to thirty. Thirty times two equals sixty. Twelve multiplied by five equals sixty. While they debate their answer, let's review! Remember, in word problems, estimating to check whether our answers are reasonable is a useful skill. First, read and reread the problem to identify the important information. Then round or change the numbers to ones that are easier to work with, or that we can use known facts to solve. Next, use mental maths to find an estimate. Finally, compare the estimation to the original answer to determine whether it is reasonable. Congratulations Imani, and you too, Mr. Squeaks!
Estimation Word Problems exercise

How can you use estimation to help check a word problem?
HintsIn any process, the first step is always to look at, observe or read the information.
We would decide to use rounding and/or known facts before mental maths.
SolutionWhen using estimation in word problems:
 First read, then reread the problem to identify the important information.
 Next, use rounding or known facts.
 Then, use mental maths to find an estimate.
 Finally compare the estimate to the original answer to determine if it is reasonable or not.

Is the answer reasonable, or not?
HintsWhen rounding, round to the closest 5 or 10.
Examples:
17 becomes 20.
63 becomes 65.Compare your estimation to the original answer to determine if it is reasonable or not.
If the answers are close, then the original answer is reasonable.If there is a large difference, more than 20 or so, then it is not reasonable.
Solution Zuri collected 6 boxes with 24 cans in each.
6 x 25 = 150 Freddie collected 4 boxes with 37 cans in each.
4 x 40 = 160 Freddie has about 160 cans.
160  150 = 10
Freddie has about 10 more cans than Zuri. Freddie's claim that he collected 292 more cans than Zuri is not reasonable.

How could we use estimation to check this problem?
HintsWhen rounding, estimate to the closest 5 or 10.
Examples:
17 becomes 20.
63 becomes 65.Each of Bill's 23 guests receives 2 small toys.
This suggests we need to multiply to find the correct answer.Solution Bill invited 23 guests, so round 23 up to 25.
 Bill wants to give 2 small toys to each guest, so multiply 25 by 2.
 2 x 25 = 50.
 Bill and Marty need to buy about 50 small toys for the gift bags.

Solve the word problem using estimation.
HintsWhen rounding, round to the closest 5 or 10.
Examples:
17 becomes 20.
63 becomes 65.Compare your estimation to the original answer to determine if it is reasonable or not.
If the answers are close, then the original answer is reasonable.If there is a large difference, more than 20 or so, then it is not reasonable.
Solution1) £5.85 can be rounded down to £5.00.
£14.90 can be rounded up to £15.00.
2) £5.00 x 11 = £55.00.
£15.00 x 10 = £150.00.
3) £55.00 + £150.00 = £205.00.
Marie's guess of £400.00 for flowers is not reasonable.

What would be a reasonable answer?
HintsWhen rounding, round to the closest 5 or 10.
Examples:
17 becomes 20.
63 becomes 65.We can round £4.89 to £5.00.
We then need to multiply £5.00 x 8 to get a reasonable estimate.
SolutionThe correct answer is £40.00.
£4.89 can be rounded to £5.00.
We can then multiply £5.00 x 8 to get £40.00.
£40.00 is a reasonable estimate for the total cost.

Use estimation to solve the word problem.
HintsWhen rounding, round to the closest 5 or 10.
Examples:
17 becomes 20.
63 becomes 65.To find how many pens Drew needs in total, multiply 10 (each person gets 10 pens) by the number of people who need them. Use the rounded number.
To find how many packs of pens Drew needs, take the total number of pens needed and divide by 5 (there are 5 pens in each pack).
For the final question, write either 'reasonable' or 'not reasonable'.
Solution 4 people can be rounded up to 5.
 10 pens x 5 people = 50.
 50 pens ÷ 5 = 10.
 Drew's guess that he needs 10 packs of pens is reasonable.