A box factory in one day made 74 small boxes, 129 medium boxes, and 351 large boxes. They sold 257 boxes. Estimate how many boxes they still had in the factory

Question

i am not sure what i need to do or what the answer is if i estamate this 

Answer 1

The exact answer is:

     74 + 129 + 351 - 257  =  297

 

Now, how long would it take you to perform that calculation?  And, if you didn't have your calculator handy, how long would it take?

 

Estimating is a quick method of getting a close answer.  It is also very useful when you want to verify that exact calculations are correct.

 

So, for this problem, what is:

     75 + 130 + 350 - 255  ?

         205 + 350 - 255   ?

            555 - 255   ?

              300                   [note: "close" to 297]

 

  or, what is:

        75 + 125 + 350 - 250   ?

           200 + 350 - 250   ?

             550 - 250   ?

               300

 

Now, you may notice that multiples of 10 are easier to add and subtract than multiples of 5.  To adjust for possible errors, we make some numbers bigger and some numbers smaller so that the final result will remain "close" to the exact answer.

 

Each problem will have some "better" solutions.