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❓ Missing Box

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I can find the missing number in a number sentence.

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📖 Learn first

Undo the operations in reverse order to find the missing number.

Example: 3 × □ + 5 = 20

  1. 20 − 5 = 15
  2. 15 ÷ 3 = 5

Questions get harder as you go. The last ones ask you to type the answer.