Mike N. answered • 10/06/14
Tutor
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Professional Mathematician with homeschool experience
Your question is a little vague...
But perhaps you mean something like this:
Estimate 3 4/5 + 2 1/9.
Well, our plan is to replace the fixed fractions with nice friendly whole numbers by rounding to the nearest integer. Starting with the first number, 4/5 > 1/2, so 3 4/5 is closer to 4 than to three. As to the second number, 1/9 < 1/2, so 2 1/9 is closer to 2 than to three. So, we replace the 3 4/5 with 4, and the 2 1/9 with 2:
4 + 2 = 6.
Our estimate is 6. The actual answer is 5.91, so our estimate was very good.
You can find some material to read here: https://ck12.org/arithmetic/Mixed-Number-and-Fraction-Estimation/lesson/Mixed-Number-and-Fraction-Estimation/
