Word Problems : Estimating

In your groups, solve the following word problems.

   Estimate the sum or difference by rounding each number to the nearest ten.

1)      Sam picked 374 lemons and Tim picked 929 lemons from the lemon tree. Estimate how many lemons they both picked ?

2)       Alyssa's Cupcake Shop sold a total of 586 cupcakes today, and 213 of those had sprinkles. Estimate how many cupcakes were sold without sprinkles?

3)       There were 378 scissors in the drawer and Nancy put away 324 more . Estiamte how many scissors are now in the drawer?

Now estimate the sum or difference by rounding each number to the nearest hundred.

4)       John has 678 baseball cards. Benny bought 347 of John's baseball cards. Estimate how many baseball cards  John still owns?

5)       Keith found 935 seashells on the beach and  he gave Melanie 126 of them. Estimate how many seashells  he now has?

6)     Sally and Alyssa decided to bake cookies for the family picnic. Sally baked 611 raisin cookies and Alyssa baked 649 sugar cookies. Estimate how many cookies they baked altogether?

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Estimation is a Skill for Life!

As you walk around and live your life, imagine if you could easily estimate:

• how much a bill will be,
• which item is the best value for money
• the size, areas and angles of things

Also, it would be great if you could quickly guess how many people are in a room, how many cars in the street, how many boxes on the shelf, or even how many seagulls on the beach?

We are not talking exact answers here, but answers that are good enough for your life.

                             Exact vs Estimate

In mathematics we often stress getting an exact answer. But in everyday life a few cents here or there are not going to make much difference ... you should focus on the dollars! Estimation is ...... finding a number that is close enough to the right answer. You are not trying to get the exact right answer What you want is something that is good enough (usually in a hurry!)                                            Why?1.Estimation can save you money. Always do a quick estimation of how much you should pay: Example: you want to buy five magazines that cost $1.95 each. When you go to buy them the cost is $12.25. Is that right? "five at $1.95 each is about 5 times 2, or about $10" so $12.25 seems too much!  Ask to have the total checked. 2.Estimation can save you time (when the calculation does not have to be exact) Example: you want to plant a row of flowers. The row is 58.3cm long. The plants should be 6cm apart. How many do you need? "58.3 is nearly 60, and 60 divided by 6 is 10, so 10 plants should be enough." 3. Estimation can save you from making mistakes with your calculator: Example: you are calculating 107 times 56, and the calculator shows this: 952 Is that right? "107 times 56 is a bit more more than 100 times 50, which is 5.000"  Ooops! you must have typed something wrong ... ... in fact you pressed 17×56 (you left out the zero), and without estimating you could have made a really big mistake! Estimation helps you focus on what is really going on. It helps you to check your Math resolutions as well! Estimation helps with your Confidence, Judgement and Decisions

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