4th grade
posted by Nancy on .
Explain how you would use frontend estimation to subtract 189 from 643.

640  190 = ?
http://www.aaamath.com/est73ax3.htm
http://www.basicmathematics.com/frontendestimation.html 
dont know

how you would use frontend estimation to subtract 189 from 643 explain

i think it would be 990 or 1,000

estimate to sutract 189 from 643