Missing Addends Quiz/Game
Counting on is one great way to find a missing addend, especially when the numbers aren’t too large. You can count up from the number you know until you reach the total. For larger numbers, you may consider using subtraction. Scroll down the page for a more detailed explanation.
 
In this game, you will practice finding the missing addend in an addition problem. This game will allow you to set the maximum sum, making it easy to adjust the difficulty. It will also include a timer, a scoring system, and clear feedback to help you master this skill.
 

Missing Addend

Find the missing number to complete the equation.

Maximum Sum:

Enable 60-Second Timer

Start Game

Score: 0 / 0

Time: 60

Check Next

Back to Menu

 

How to Play the Missing Addends Game
The game will show an equation with a missing addend. Your task is to find the missing addend.
Here’s how to play:

1. Maximum Sum: Enter the maximum sum to adjust the difficulty.
   
2. Timed Option: Check the timer if you want to enable the 60 second timer. Click “Start Game”.
   
3. Look at the Problem: You will be given an equation with a missing addend.
   
4. Enter Your Answer: Fill in the blanks to complete the equation.
   
5. Check Your Work: Click the Check button (or press the Enter key). The game will tell you if you’re correct. If you are wrong, you will be shown the correct answer.
   
6. Get a New Problem: Click the Next button for a new problem.
   Your score is tracked at the top, showing how many you’ve gotten right out of the total you’ve tried.
   
7. Back to Menu Click “Back to Menu” to restart the game.
    
   How to Missing Addends
   Missing Addends
    
   For small numbers, we may use the count-on strategy.
   Let’s use the example: 15+__=18.
   Start with the number you know. This is the first addend, which is 15.
   Count on to the sum. Now, you count up from 15 until you reach the sum, which is 18.
   You start at 15.
   Count: 16 (that’s one count)
   Count: 17 (that’s two counts)
   Count: 18 (that’s three counts)
   The number of counts is your answer. You counted up a total of 3 times. That means the missing addend is 3.
   So, 15+3=18.
    
   This is a great strategy to use in your head and it helps reinforce the relationship between the numbers in an equation.
    
   

For larger numbers, we may use subtraction to find the missing addend.
Step-by-Step Example
Let’s solve the problem 25 +__ = 49.
Identify the sum. The total or sum is 49.
Identify the addend you know. We already know one of the addends is 25.
Create a subtraction problem. You can rewrite the problem to find the missing number. Start with the sum and subtract the addend you know.
49 − 25 =__
Solve the subtraction. When you subtract 25 from 49, you get 24.
49 − 25 = 24
So, the missing addend is 24. The completed equation is 25 + 24 = 49.
 
This same strategy works no matter where is the missing number.

This video gives a clear, step-by-step approach to learn how to find missing addends.

• Show Video

 

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