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Adding decimals is very similar to adding whole numbers, but with one important rule: you must keep the decimal points lined up so that you are adding the correct place values together.
Decimal Addition Game
This game is designed to test your ability to organize the decimals by place value before performing addition. Scroll down the page for a more detailed explanation.
How to Play the Decimal Addition Game
The Goal
You are given two decimal numbers with different lengths. You must move them until their decimal points (the red dots) are in the exact same vertical column, then calculate their sum.
Step-by-Step Instructions
Step 1: Align the Decimal Points
When the game starts, the numbers are usually “scrambled” horizontally.
Use the Shift Left and Shift Right buttons for Row 1 and Row 2.
Move the rows until the red cells are perfectly stacked on top of each other.
Try to also align with the decimal point in the sum.
Once they are aligned, the status message will turn green and say: “ALIGNED! Enter the sum."
Step 2: Solve the Sum
Now that the numbers are aligned, the Sum input boxes will appear at the bottom.
Add the numbers column by column, starting from the right (the smallest decimal place) and moving to the left.
Pro Tip: If one number is shorter than the other, imagine a placeholder zero in the empty space to help you add.
Step 3: Check and Score
Click Check Answer.
Green boxes: Your digit is correct.
Red boxes: Something is wrong. Re-add that column.
The Zero Rule: If the last digit of the answer is a 0, the game allows you to leave that box empty (e.g., 12.50 can be entered as 12.5).
The video gives a clear, step-by-step approach to learn decimal additions.
Try out our new and fun Fraction Concoction Game.
Add and subtract fractions to make exciting fraction concoctions following a recipe. There are four levels of difficulty: Easy, medium, hard and insane. Practice the basics of fraction addition and subtraction or challenge yourself with the insane level.
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