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How to Do Long Division: Step-by-Step Instructions

A long division problem on a blackboard
A long division problem is no reason to panic. You've got this. Stephen Rees / Shutterstock

In math, few skills are as practical as knowing how to do long division. It's the art of breaking down complex problems into manageable steps, making it an essential tool for students and adults alike.

This operation has many practical uses in our daily lives. For instance, imagine you have a bag of 2,436 candies and want to share them equally among 4 friends. Long division helps you determine that each friend gets 609 candies, ensuring everyone gets their fair share.

Let's dive into the fundamentals of long division and learn about other everyday situations where we can put it to use.

What Is Long Division?

Long division is a handy way to divide big numbers by smaller ones, helping us figure out how many times one number fits into another. It turns a tricky math problem into easier steps.

When we do long division, we work with four main parts:

  • the big number we want to divide (called the "dividend")

  • the smaller number we're dividing by (the "divisor")

  • the answer to our division (the "quotient")

  • sometimes a little bit left over (the "remainder")

Long Division vs. Short Division

Short and long division are both methods to divide numbers, but they differ in complexity. The short-division method is a quick way to find the answer when dividing simple numbers. For example, say you want to divide 36 by 6. You write it as 36 ÷ 6, using a division sign, and quickly get the answer, which is 6.

Long division is used for bigger, more complicated numbers, typically two or more digits. This method involves several steps, like writing out the numbers neatly and carefully.

How to Do Long Division in Simple Steps

Let's dive into long division with a clear example. We'll use 845 ÷ 3 to walk through this step-by-step process:

  1. Set up the problem. Write the dividend (845) under the division bar and the divisor (3) outside the bar.

  2. Divide. Look at the first digit of the dividend (8). How many times does 3 go into 8? Twice, because 3 x 2 = 6, and that's the closest we can get without going over. Write the 2 above the division bar, over the 8.

  3. Multiply. Multiply the quotient (2) by the divisor (3). (2 x 3 = 6). Write 6 under the 8.

  4. Subtract. Subtract 6 from 8 to get 2. Draw a line under the 6, subtract, and write 2 below the line.

  5. Bring down the next digit. Now, bring down the next digit of the dividend, which is 4, to sit next to the 2, making 24.

  6. Repeat the steps. 3 goes into 24 eight times (3 x 8 = 24), so write 8 above the bar next to the 2. Subtract 24 from 24 to get 0. Now, follow the same process you used in steps 1 through 5 and bring down the last digit, which is 5, to form 05. The number 3 goes into 5 once (3 x 1 = 3), leaving a remainder of 2. Write the 1 above the bar and the remainder 2 below after subtracting 3 from 5.

  7. The final answer with a remainder. You've divided 845 by 3 to get a final answer of 281 with a remainder of 2.

  8. Convert the remainder to decimal form. Depending on how far along you are in learning long division, this may be your final answer. If you've progressed to decimals, you will add .0 to 845 and put a decimal point above the division bar, right after the 1. Bring 0 down to form 20. The number 3 goes into 20 six times (3 x 6 = 18). Write 6 after the decimal point above the division bar. Normally, you would continue adding another 0 after 845. until there is no remainder, but since 20 – 18 = 2, you would be repeating this process infinitely because 3 does not divide evenly into 845. Instead, you will draw a horizontal line over the 6 in 281.6 to indicate that it is a repeating decimal. A calculator would show the answer as 281.666667 to indicate that the repeating decimal rounds up.

Long Division Method: An Apple Example

Now let's use a practical example to work through the long division process.

Imagine you just went apple picking and came home with a massive haul of delicious fruit. In your kitchen, you have 456 apples, and you want to share them equally among 3 baskets to give to your friends, so you're dividing 3 by 456 (456 ÷ 3).

To figure out how many apples go into each basket, you'd tackle the division problem step by step.

  1. 3 goes into the first digit (4) once, so you write 1 above the division bar, above the 4 in 456. Then you show the subtraction: 4 – 3 = 1.

  2. Bring down the next digit (5) to form 15. 3 goes into 15 five times (3 x 5 = 15), so you write 5 above the division bar, above the 5 in 456. Then you show the subtraction: 15 – 15 = 0.

  3. Bring down the final digit (6) to form 06. 3 goes into 6 twice (3 x 2 = 6), so you write 2 above the division bar, above the 2 in 456. Then you show the subtraction: 6 – 6 = 0.

  4. Since there is no remainder left to divide, you quotient is now written atop the division bar: 152. You will need to place 152 apples in each of the 3 baskets to evenly distribute the 456 apples.

Using Long Division in Everyday Life

Long division also pops up in real-life situations. Think about when you need to divide something, like pizza or cake, into equal parts.

Want to cut a large recipe in half or figure out how many days are left till summer vacation? Long division can help with that. It's a great way to help us figure out those splits and manage resources better.

And, of course, practicing long division sharpens our problem-solving skills. It teaches us to tackle big problems step by step, breaking them down into smaller, more manageable pieces. This approach is super helpful in math and figuring out all sorts of challenges we might face.

So, long division is more than just a bunch of steps we follow. It's a key that unlocks a lot of doors in the world of math and beyond, helping us understand and connect different concepts and apply them in all sorts of ways.

How to Divide a Decimal Point by a Whole Number

Dividing decimals by whole numbers is useful in our everyday lives. For instance, if you're splitting a sum of money equally among a certain number of people, you'll need to divide the total (a decimal) by the number of people (a whole number) to determine how much each person gets.

Dividing a decimal point (decimal number) by a whole number is similar to regular division, but you must be mindful of the placement of the decimal point. Here's how to do it:

Example: Divide 0.5 by 5.

  1. Set up the problem. Begin by setting up the division, with 0.5 as the dividend (the number you're dividing, which will be under the division bar) and 5 as the divisor (the number you're dividing by, which will be to the left of the division bar).

  2. Begin dividing. 5 goes into the first digit of the dividend 0 times, so you'll write 0 above the division bar, above the 0 in 0.5, and place a decimal point after the 0 you just wrote. It should be directly above the decimal point in the dividend.

  3. Bring down the next digit. Bring down the 5 to form 05 (you do not bring the decimal down). 5 goes into 5 once (5 x 1 = 5), so you'll write 1 above the division bar, above the 5 in 0.5.

  4. Show the final answer. When you show the subtraction (5 – 5 = 0), you'll have no remainder. This means the number above the division bar is your final answer: 0.1.

Practice Problems and Answers

Let's put our long division skills to the test with some word problems. Tackle these problems one step at a time, and don't rush. If you get stuck, pause and review the steps. Remember, practice makes perfect, and every problem is an opportunity to improve your long-division skills.

1. Emma has 672 pieces of candy to share equally among her 4 friends. How many pieces of candy does each friend get?

Solution: To find out, divide 672 by 4. Start with the first part of 672, which is 6, and see how many times 4 can fit into it. It fits 1 time, leaving us with 2. Bringing down the 7 turns it into 27, which 4 fits into 6 times, leaving us with 3. Finally, bringing down the 2 to join the remaining 3 makes 32, which 4 divides into 8 times. So, each friend gets 168 pieces of candy.

2. A teacher has 945 stickers to distribute equally in 5 of her classes. How many stickers does each class get?

Solution: We'll divide 945 by 5. Looking at 9 first, 5 goes into it 1 time. With 4 leftover, we bring down the 4 from 945 to get 44, which 5 divides into 8 times with another 4 leftover. Lastly, bringing down the 5 to the remaining 4 makes 45, which 5 divides into 9 times. Therefore, each class receives 189 stickers.

3. A library has 2,310 books to be placed equally on 6 shelves. How many books will each shelf contain?

Solution: Divide 2,310 by 6. Starting with 23, 6 goes into it 3 times with 5 leftover. After subtracting, we bring down the 1 to get 51, which 6 divides into 8 times with 3 leftover. Bringing down the 0 to the remaining 3 gives us 30, which 6 divides into 5 times. So, each shelf will have 385 books.

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.

Original article: How to Do Long Division: Step-by-Step Instructions

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