Use front-end estimation to find the value of the expression. I do not understand (without adjustment)


687 - 239 (without adjustment)

is this right?

600 + 200= 800 + 126=926

5 answers

If your problem is 687 - 239, it makes sense to me to do it this way:

700 = 200 = 500
Correction:

700 - 200 = 500
Right it was subtraction. So what does "without adjustment" mean?
I'm not a math teacher -- but I assume you don't need to adjust for the small differences between your estimated numbers and the actual numbers.

This site may explain it.

http://mathforum.org/library/drmath/view/65415.html
Thank you