Estimating is one way 
to check and verify your answers 

Example A:

Shannon's family is going to an amusement park.
The park charges a flat price of $24.
If there are 4 people total in Shannon's family,
About how much will it cost to enter the park? 

Solution A:

Think & Estimate:
24 is "about" 25,
and 25 x 4 = 100.

So, it will cost Shannon's family
about $100

Example B:

There are 21 students in Tom's class.
He wants to bring in cupcakes 
to celebrate his birthday.
The store only sells cupcakes by the 1/2 dozen package.
How many packages will Tom need to buy, 
so everyone in his class gets 1 cupcake?

Solution B:

Think & Estimate:
A 1/2 dozen = 6
6x1=6, 6x2=12, 6x3=18, and 6x4=24
18 is not enough for 21 students,
and 24 is more than 21.

So, Tom should buy 4 packages of cupcakes
to assure that all of his classmates get one.

Remember:       

  Estimating
 is one way to check and verify
         your answers.      

Let's Practice