Finding Unknown Numbers

Grade 1 Math | Solving for Missing Numbers

18 minutesBeginnerProblem Solving

What are Unknown Numbers?

Sometimes in equations, we have a missing number that we need to find. This missing number is called an "unknown"!

We can use different symbols to show the unknown number:

  • A box: □
  • A question mark: ?
  • A blank space: ____
  • A letter (later): like x

Our job is to figure out what number goes in the unknown place to make the equation true!

To find the unknown number, we think: "What number makes both sides equal?"

Examples of Unknown Numbers

3 + □=7

What number goes in the box?

Answer: 4

?=2 + 3

What number equals 2 + 3?

Answer: 5