YourHomeschool YourHomeschool Curriculum By state Workbooks Open the Tutor
Curriculum › Grade 3 › Mathematics

Find the Missing Number

Aligned to 3.OA.A.4 — Common Core State Standards for Mathematics.

What this lesson teaches

Sometimes one number in an equation is hidden. Use facts you know to find the number that makes the equation true.

Worked example

Solve 4 × ? = 24. Ask: 4 times what equals 24? Count by 4s: 4, 8, 12, 16, 20, 24. That is 6 fours. So the missing number is 6, because 4 × 6 = 24.

Practice questions

  1. Find the missing number: 3 × ? = 15.
  2. Find the missing number: ? × 5 = 40.
  3. Find the missing number: 28 ÷ ? = 7.

Watch the lesson

Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.

▶ Watch this lesson

En español

Encuentra el Número que Falta

A veces un número de la ecuación está escondido. Usa los hechos que ya sabes para encontrar el número que hace verdadera la ecuación.

Ejemplo: Resuelve 4 × ? = 24. Pregunta: ¿4 por cuánto es 24? Cuenta de 4 en 4: 4, 8, 12, 16, 20, 24. Son 6 cuatros. El número que falta es 6, porque 4 × 6 = 24.

More Operations & Algebraic Thinking lessons

Multiplication and Division within 1003.OA.A.3Multiply with Equal Groups3.OA.A.1Divide into Equal Shares3.OA.A.2Smart Ways to Multiply3.OA.B.5Division as a Missing Factor3.OA.B.6Know Your Facts by Heart3.OA.C.7

Teach this lesson today

An AI tutor that guides with questions instead of just giving answers — all K–12 core subjects, every child in the family.

Start free — no card required