Question

Mrs.Kennedy is buying pencils for each 315 students at Hamilton Elementary.The pencils are sold in boxes of ten.How can she use rounding to decide how many pencils to buy?

Answer 1

She is buying 1 pencil each for 315 students. So that means she has to buy a total of 315 (315 x 1 = 315) pencils.

However, she has to buy the pencils in packs of 10. So, 315/10 = 31.5

But the problem is that she cannot buy half a box. And if she needs 315 pencils, she can not buy 31 packs because then she will need 5 more pencils. So it is better for her to buy 32 packs and get 5 extra pencils.

In questions like this, you need to always round up. Even if she needed 311 pencils, she would still have to buy 32 boxes.

Hope that helped :)

Answer 2

Mrs. Kennedy is buying 315 pencils
But pencils are sold in boxes of 10
How can she use rounding in this given situation

315 = number of pencil she wants to buy
10 = number of pencils per box
=> 315 / 10
=> 31.5, Since she needs 315 pencils, she need to buy 31 boxes and half.
However, they are not selling half box. So Mrs. Kennedy needs to round off the number of pencils to buy to its nearest value.
Since the value next to the decimal points is 5, Mrs. Kennedy will round up.
Therefore, Mrs. Kennedy will now buy 32 boxes of pencils or equals to 320 pencils.