Find the Missing Number
Work out the missing number in each equation, then match it to its answer. The blank moves around — sometimes it's an addend, sometimes the number you take away, sometimes the total — so you get to think it through every way. Tap an equation, then tap the number that makes it true, and watch the pair link. Aligned to Common Core 1.OA.D.8 — finding the unknown whole number in an addition or subtraction equation, in any position.
Work out the missing number in each equation, then match it to its answer. The blank moves around — sometimes it's an addend, sometimes the number you take away, sometimes the total — so you get to think it through every way. Tap an equation, then tap the number that makes it true, and watch the pair link. Aligned to Common Core 1.OA.D.8 — finding the unknown whole number in an addition or subtraction equation, in any position.
About this activity
This free, interactive activity gives children hands-on practice with early addition and subtraction ideas, working with quantities up to . It plays straight in the browser on any device, with nothing to install and no login.
It is aligned to Common Core 1.OA.D.8 in the Operations & Algebraic Thinking strand. Feedback is immediate and encouraging, and there is no timer or score — children can think things through at their own pace.
What's inside this activity
- Designed for Grade 1 learners (ages about 5 to 9)
- Common Core strand: Operations & Algebraic Thinking
- Aligned to Common Core standard 1.OA.D.8
How to play
Children read the prompt and look at the groups of objects on the screen.
They combine, separate, or choose to answer the question.
A friendly check shows when they are right, with a relaxed chance to try again.
What your child practices
- Putting groups together and taking them apart to find how many
- Seeing different ways to make the same number
- Solving simple word-problem situations with pictures and counters
- Reasoning about quantities up to
Learning goals
Add and subtract within small numbers using objects and pictures.
Understand addition as putting together and subtraction as taking apart — the idea behind Common Core 1.OA.D.8.
Develop the flexible number sense that fluent mental math is built on.
Frequently asked questions
- What does the Find the Missing Number activity teach?
- Find the Missing Number is a free interactive activity for Grade 1, focused on Operations & Algebraic Thinking. Children play it right in the browser — no printing, login, or setup required.
- Is Find the Missing Number free to use?
- Yes. Find the Missing Number is completely free, with no signup and no paywall, on any tablet, laptop, or classroom whiteboard.
- Which ages is this activity for?
- It is designed for Grade 1 (Operations & Algebraic Thinking) and works well for whole-class, small-group, or independent practice.