You want to buy 8 books for $19.68 each, estimate the total cost show your work.

I did 19.68 x 8 and got 157.44

then rounded the answer and got 157 am I right?

Or

The second time I tried I estimated 19.68 and got 20
so then I did 20 x 8 and got 160
Is this right?

Your second estimate is correct.

Your second answer is correct.

Thanks!

You're welcome.

To estimate the total cost of buying 8 books at $19.68 each, there are two methods you can use. Let's go through both methods and evaluate their accuracy.

Method 1:
You correctly multiplied the price of one book, $19.68, by the quantity of books, 8:
19.68 x 8 = 157.44

For rounding purposes, you rounded the answer to the nearest whole number, obtaining 157. This method is appropriate if you only need an approximate total cost. However, keep in mind that rounding introduces some degree of inaccuracy.

Method 2:
In this method, you rounded the price of one book, $19.68, to the nearest whole number, which is 20. Then you multiplied this rounded price by the number of books, 8:
20 x 8 = 160

This method involves rounding the price per book rather than just the final answer. While using this method allows for a simpler calculation, it may introduce more significant inaccuracies in the result.

Comparing the two estimates, the first method (157) seems to be a more accurate representation of the actual total cost. However, remember that it is an estimation, and the exact total cost may still vary slightly.