Estimating sums and differences of mixed numbers means finding an approximate answer rather than the exact one. You round each mixed number to a whole number or an easy fraction before adding or subtracting.
Estimation helps you decide whether your exact answer makes sense. It gives you a quick way to predict or check your work.
To estimate the sum of mixed numbers, round each number to the nearest whole number, then add them together.
When rounding, fractions greater than or equal to 12 round up to the next whole number. Fractions less than 12 round down.
To estimate the difference of mixed numbers, round each mixed number to the nearest whole number, then subtract the smaller from the larger.
Estimation gives a quick check to see if your exact subtraction is reasonable. Always compare your estimated and actual results.
Estimation helps you make quick and reasonable decisions without detailed calculations. It is useful in real-life situations such as measuring, shopping, or comparing quantities.
Estimation helps you check for reasonableness and make faster mental calculations in everyday tasks.