Fixit's Fix-It Corner — Find the Missing Number (Grade 1)
A free interactive Grade 1 math game for the missing number in addition and subtraction: help Fixit the near-sighted repair-mole work out the part each broken gadget needs — the missing sum, addend, subtrahend, or minuend — then pop it in and watch it whir to life. Counting-on, fact-families, and balancing all build Common Core 1.OA.D.8.
A free interactive Grade 1 math game for the missing number in addition and subtraction: help Fixit the near-sighted repair-mole work out the part each broken gadget needs — the missing sum, addend, subtrahend, or minuend — then pop it in and watch it whir to life. Counting-on, fact-families, and balancing all build Common Core 1.OA.D.8.
About this activity
Fixit the repair-mole needs the missing number to fix each broken gadget, so the child finds the unknown part of an equation — the missing sum (8 + 5 = ?), a missing addend (8 + ? = 13), a missing subtrahend (13 − ? = 8), or a missing minuend (? − 5 = 8) — then drops it in and watches the gadget whir to life. It's a free, interactive Grade 1 math game played in the browser on any device with no sign-up.
The big idea is that the equals sign means 'the same as,' so the unknown can sit in any position, not just at the end. Early rounds let the child count countable objects and even count on or count back; later rounds fade the supports and use fact-family triangles, recombining, and a balance round like 6 + 6 = ? + 4 where both sides must match. The child reasons about the whole and its parts instead of just adding from left to right.
It is aligned to Common Core 1.OA.D.8 — determining the unknown whole number in an addition or subtraction equation with the unknown in any position. No timer, no score — just calm, playful practice.
What's inside this activity
- Designed for Grade 1 learners (ages about 6–7)
- Common Core strand: Operations & Algebraic Thinking
- Aligned to Common Core standard 1.OA.D.8
How to play
Read the broken gadget's equation and see which number is missing.
Work out the missing part — count on, count back, or use the fact family.
Pop your answer in to fix the gadget; try again freely, with no timer and no score.
What your child practices
- Finding the unknown in any spot — the sum, an addend, the subtrahend, or the minuend
- Counting on and counting back to find a missing part
- Using fact families to relate addition and subtraction
- Balancing both sides of an equation so they are truly equal
Learning goals
Find the unknown number in an addition or subtraction equation in any position — the focus of Common Core 1.OA.D.8
Understand the equals sign as 'the same amount on both sides'
Build the part-whole and fact-family reasoning that fluent computation depends on
Frequently asked questions
- What does the Fixit's Fix-It Corner — Find the Missing Number (Grade 1) activity teach?
- Fixit's Fix-It Corner — Find the Missing Number (Grade 1) 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 Fixit's Fix-It Corner — Find the Missing Number (Grade 1) free to use?
- Yes. Fixit's Fix-It Corner — Find the Missing Number (Grade 1) 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.