How do you estimate the sum and difference of decimals?

Students learn to estimate the sum or difference of two decimals by first rounding each decimal to the nearest whole number, then adding or subtracting. For example, to estimate the sum of 4.94 and 2.185, round 4.94 up to 5, and round 2.185 down to 2, to get 5 + 2, which equals 7.Click to see full answer. Similarly, should you estimate when adding or subtracting decimals?It also lets you check to be sure an exact answer is close to being correct. Estimating with decimals works just the same as estimating with whole numbers. When rounding the values to be added, subtracted, multiplied, or divided, it helps to round to numbers that are easy to work with.Subsequently, question is, how does estimating the answer help you to know that you place the decimal point in the sum correctly? That’s easy when you estimate you are finding the whole number of which the decimal is closest to. When you place the decimal you count all the numbers behind the decimal point on the other numbers. Then you move the decimal don that very spot. Then, how do you estimate a sum with rounding? You can round each addend to the nearest hundred to estimate the sum. Estimate the sum 1,472 + 398 + 772 + 164 by rounding each number to the nearest hundred. First, round each number to the nearest hundred. Then, add the rounded numbers together.How do we multiply decimals? Multiply the numbers just as if they were whole numbers. Line up the numbers on the right – do not align the decimal points. Starting on the right, multiply each digit in the top number by each digit in the bottom number, just as with whole numbers. Add the products.