# Estimating Decimal Sums and Differences Worksheets

You will find this skill to be very helpful in life. Doing math quickly can help us make better decisions and suggestions to others. People that make strong decisions and suggestions usually become more successful in life. Estimation allows us to do basic math operations much quicker. This is simply because there is less math to do. You will find that you will do this a great deal when you are selling or buying something. These worksheets help students learn how to get a rough estimate of the end value of decimals that are being added or subtracted.

### Aligned Standard: 5.NBT.7

- Word Based Step-by-Step Lesson- Read carefully and follow the directions.
- Guided Lesson - I find this to be a great reading comprehension lesson as well. Have the kids outline what they need to do.
- Guided Lesson Explanation - Round them and then add them or subtract them.
- Estimating Sums and Differences with Decimals 5 Pack - This is best served with the numbers being vertically laid out.
- Practice Worksheet - A nice rapid fire math exercise for you. The chief is the symbol of the Poconos Warriors (Elementary) that helped me with this sheet.
- Matching Worksheet - Match the description with the estimated final value.

- Answer Keys - These are for all the unlocked materials above.

### Homework Sheets

Talk about knowing your math sentences. These sheets don't ask, they demand it!

- Homework 1 - Estimate the sum of 2.420 and 7.862 by rounding to the nearest hundredth.
- Homework 2 - Another round of the previous worksheet for you.
- Homework 3 - More sums to focus on here.

### Practice Worksheets

I highly recommend that you circle the play values in question whenever possible.

- Practice 1 - Estimate the place value first.
- Practice 2 - Make sure that all place values jive.
- Practice 3 - Sometimes it will make more sense to estimate other place values first.

### Math Skill Quizzes

We are really just worried about rounding to the nearest tenth and hundredth here.

- Quiz 1 - Sums of decimals that ride our to the thosandths place.
- Quiz 2 - We give you yet another to work on.
- Quiz 3 - These can be tricky.

### How to Estimate Sums and Differences

Estimation is a concept that we use when we are not looking for the perfect solution, but just a good idea of where the solution is located. We often do this when we are determining the price of things. Meaning that in the estimation, we can find an answer that can work with the problem even if it's not accurate. You can estimate the sums and the differences by rounding off the numbers to the nearest tens, hundreds or thousands. It simply depends on how accurate you need to be. After you round off the numbers, you can use your mental math skills to solve them. Let's take two examples each for the addition and subtraction of numbers.

Firstly, we have to add two numbers, 322 and 178 together. Now, let's round off the numbers to 300 and 200 (the hundreds place) respectively. If we add 300 and 200, we will get an answer of 500 and that is the estimated answer. This solution is funny because it is also the exact solution too.

Secondly, let's subtract 223 and 110 together. Now, let's round off to the closest hundreds, i.e., 200 and 100. Now, if we subtract the numbers, we will get answer 100 which is the estimated results. This difference differs a bit more from the actual solution of 113.

As the values that you work with get much larger, rounding the front end gets less accurate. You simply need to be aware of what level of accuracy you are expecting in your outcome. If you were looking for a sum or a difference between values such as 1,587,201 and 18,259,745; the level of accuracy greatly increases with rounding to the lower place values.