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Practice dividing decimal amounts into equal groups using whole number divisors.
Imagine you and three friends find a treasure chest with exactly $10.44 inside. How do you split it so everyone gets the exact same amount down to the very last penny?
Dividing decimals might look scary, but it is almost exactly like dividing whole numbers. The most important secret is the Decimal Placement. When you set up a long division problem, the decimal point in your answer (the quotient) goes directly above the decimal point in the number being divided (the dividend).
Think of the decimal point like a button on an elevator—it just travels straight up to the roof! Once the decimal is in place, you can ignore it and divide just like you always have. You'll use the same steps: Divide, Multiply, Subtract, and Bring Down.
Let's divide by .
1. Set up the long division: 2. Move the decimal point straight up: becomes with the decimal ready in the answer space. 3. Divide by : . Write above the . 4. Divide by : . Write above the . 5. The final answer is .
Quick Check
If you are dividing by , where should the decimal point in your answer be located?
Answer
Directly above the decimal point in 15.5, between the two digits of the quotient.
Sometimes, when you reach the end of the number, you still have a remainder. In decimal division, we don't like remainders! Instead, we use the Zero Hero.
Since is the exact same value as or , you can add as many zeros as you need to the end of the decimal to keep the division going. This allows you to find a precise answer instead of leaving a leftover piece. Just 'annex' (attach) a zero to the dividend and bring it down to continue your work.
Three friends want to split a lunch bill of equally.
1. Set up: . 2. Place the decimal point straight up above the line. 3. . Write above the . 4. . Write above the . 5. . Write above the . 6. The result is . Each friend pays .
Quick Check
What should you do if you finish dividing all the digits but still have a remainder left over?
Answer
Add a zero to the end of the decimal dividend and keep dividing.
What happens if the divisor is larger than the first digit? For example, . Since cannot go into , we place a in the ones place of our quotient.
It is vital to keep your columns neat and organized. If you shift a number to the left or right by mistake, your decimal point will end up in the wrong spot, and your answer could be times too big or too small! Always use a leading zero (like ) to make your decimal point easy to see.
You have a meter ribbon and need to cut it into equal pieces. How long is each piece?
1. Set up: . 2. Move the decimal up. 3. goes into zero times. Write above the . 4. goes into two times (). Write above the . Subtract to get . 5. Annex a zero to make it . Bring down the to make the remainder . 6. goes into five times. Write in the next spot. 7. Answer: meters.
What is ?
If you are dividing by , what is the first step?
Adding a zero to the end of a decimal (like changing to ) changes the value of the number.
Review Tomorrow
In 24 hours, try to explain the 'Elevator Rule' for decimals to a friend or family member.
Practice Activity
Find a receipt from a grocery store. Pick an item price and try to divide it by 2 or 4 to see how much half or a quarter of that item would cost!