Welcome 5th grade teachers! This blog post will help you teach decimal long division. This skill can take a lot of repetition to master, especially when it comes to remembering to move the decimal point to the correct place at the end. That’s why I’m giving you a quick breakdown on how to do decimal long division along with a free activity that your students can use to practice this skill.
In order to master this decimal long division, it’s important that we first look at some basic information and definitions.
- Long Division Definition: Long division is a method of dividing two numbers where the result has a whole number and remainder.
- Decimal Definition: A decimal is a numerical value that is part of a real number expressed in base-ten.
Now that we have our definitions, let’s move on to how to do decimal long division.
Step 1: Introduce long division with decimals to students by providing an example problem and using it to review each of the vocabulary definitions above.
Example Problem: Divide 434.5 by 5.
Step 2: Explain step-by-step instructions for solving decimal division problems.
- Write the problem in a long division format.
- Begin by dividing the whole number part of the dividend (434) by the divisor (5). Record the answer below and to the left. 43 divided by 5 is 8 so you’ll write an 8 above the 3.
- Multiply your answer (8) by 5 and write it underneath the line, then subtract that number from what’s in parentheses. 8 x 5 = 40 so you’ll write 40 underneath the line and subtract it from 43.
- You’ll then bring down the rest of the dividend (the 4) to get the number 34 and repeat the same steps. 5 goes into 34 a total of 6 times. So you’ll write the 6 above the 4.
- Multiply your answer (6) by 5 and write it underneath the line, then subtract that number from what’s in parentheses. 6 x 5 = 30 so you’ll write 30 underneath the line and subtract it from 34. 5.You’ll then bring down the rest of the dividend (the 5) to get the number 45 and repeat the same steps. 5 goes into 45 a total of 9 times. So you’ll write the 9 above the 5.
- Multiply your answer (9) by 5 and write it underneath the line, then subtract that number from what’s in parentheses. 9 x 5 = 45 so you’ll write 45 underneath the line and subtract it from 45. 5.This gives you an answer of 0, so you are done with this problem.
- Record your final answer in the long division format and move the decimal point straight up so it’s in the correct place in your answer.
Step 3: Practice!
Have students solve the following example problems (you can assign these as homework or do a group practice in class):
1. Divide 32.6 by 2
2. Divide 10.5 by 4
3. Divide 54.8 by 7
4. Divide 834.7 by 9
5. Divide 48.9 by 3
6. Divide 632.4 by 8
7. Divide 473.2 by 5
8. Divide 1534 by 10
9. Divide 7621 by 12
10. Divide 1492.3 by 11
11. Divide 956.6 by 6
12. Divide 7185 by 15
13. Divide 832.9 by 4
14. Divide 2346 by 16
15. Divide 5368 by 18
After students have practiced with these problems, review the answers as a class and discuss any misunderstandings or incorrect answers that may have come up during practice.
More ways to engage students in decimal long division
One way to make the review more interesting and engaging is by turning it into a game. You can create an online quiz or game that students can play in teams, with each team competing for the most points. The questions on the quiz/game should be based on the example problems from this lesson. This will help reinforce what students have learned and make the review more engaging.
Common mistakes students make when learning how to divide decimals
One common mistake that students make when learning long division is forgetting to bring down the next number from the dividend. This can lead to incorrect calculations and inaccurate answers, so it’s important to remind students of this step each time they solve a problem.
Another common mistake that students make when learning long division is not keeping their numbers lined up correctly. This can lead to incorrect calculations and inaccurate answers as well, so it’s important to remind students to keep their numbers lined up each time they solve a problem. To help them understand how this works, you can draw a line on the board and have them practice lining up their numbers below it. This will help them visualize how the process works and hopefully make it easier for them to understand.
Another mistake students might make is not correctly placing the decimal point in their final answer. This can usually be corrected by having students move the decimal point straight up from the dividend to their answer.
Finally, students might make mistakes in their calculations when multiplying or subtracting. Remind them to check their work and double-check their answers if they don’t match what’s expected. This will help catch any mistakes before they impact the final answer.
By making these corrections and reviewing their answers, students can become more accurate in their long-division calculations and improve their overall understanding of the concept.
Continue practicing decimal long division
Download this free long-division activity to practice decimal long division with your students!
That’s it for this blog post! Hopefully, you now feel comfortable teaching your students long division with decimals. If you have any questions or comments, please leave them below. Thanks for reading and happy teaching!