Free addition, subtraction and missing number game
Choose a calculation or a missing-number bond, read the equation and pick the number that fills its gap. Missing Number is free in your browser, with no account or download. There is no countdown, and each question waits until you choose an answer.
Start with addition to 10, subtraction within 10 or mixed calculations to 20. Each link selects the menu; you still choose Start.
Calculate with numbers up to 5, 10 or 20
Calculate varies the total or starting number within your chosen range. Addition asks for the result of a sum, such as 3 + 4 = ?. Subtraction asks what remains, such as 9 − 2 = ?. Addition totals stay at or below the selected maximum; subtraction never goes below zero. Zero can be an operand or answer. Mixed changes the operation from question to question.
Missing number bonds with a fixed whole
This activity keeps the whole exactly 5, 10 or 20. Addition can put the gap in either part or the total: 8 + ? = 10, ? + 2 = 10 or 8 + 2 = ?. Subtraction uses 10 − 8 = ? or 10 − ? = 2. This is fixed-bond practice, which differs from calculating across a range of totals.
Answers, completed facts and trying again
Choose two or four answer buttons in Answer choices and sound. Both settings use the same questions and deliberate pace; four choices changes the number of alternatives, not the number range. Nearby numbers provide alternatives to the correct answer.
A correct answer fills the gap and leaves the completed fact visible. Choose Next question to continue. A wrong answer also reveals the completed fact; choose Try again to hide the answer and retry that same question. Each answer counts as an attempt, including retries. Nothing advances automatically and there are no lives to lose.
Use touch or a mouse, or Tab through the native buttons and press Enter or Space. Menu returns to your activity settings. Read completed facts aloud starts off; enabling it plays the completed addition or subtraction after an answer, using pre-generated speech.
Return to your practice
Your explicit activity, operation and range choices are remembered on this browser when local storage is available. A valid activity link takes priority for that visit. Reloading returns to the menu; the current question and session tally are not saved. Clearing browser data can remove saved preferences and guest progress.
Both activities contribute to the existing Missing Number practice stickers: Number Spy at 1 correct answer, Fact Finder at 10, Fact Pro at 30 and Fact Master at 100. Fixed missing-number bonds also contribute to the shared Bonds to 5, 10 or 20 stickers. Calculate does not add to those fixed-bond totals. Completed and retried facts are supported practice, so these rewards are not independent evidence of mastery.
Open your sticker book or save the game as a favourite to find it in Your games on your next visit. For quantities you can see and mark, use counting to 10. To build an amount yourself, try Ten-Frame Fill. There is no required order for choosing these activities.
Guides featuring this game
To explore two equal groups and one more or one fewer, try Doubles Workshop: six saved visual practice routes with sums to 20.