CCSS.Math.Content.3.OA.A.4
The standard
Determine the unknown whole number in a multiplication or division equation relating three whole numbers.
Common Core State Standards for Mathematics · Operations and Algebraic Thinking
What this standard means
Students need to find the missing number in multiplication and division equations. The blank can be in any position, not just at the end. They need to understand that multiplication and division are related, so 8 × ? = 48 can be solved by thinking 48 ÷ 8.
Mastery looks like choosing a strategy, explaining it, and checking that the equation is true. Students often get stuck when the unknown is before the division sign, as in 5 = ? ÷ 3. They may also treat the equal sign as “the answer comes next” instead of “both sides have the same value.”
Ways to teach it
- Hands-on: Use counters to build 6 equal groups, then hide one factor or the total and have students write the matching equation.
- Prompt: Ask, “How can multiplication help you solve 42 ÷ ? = 6?” and have students explain with a fact family.
- Quick check: Give four equations with blanks in different positions, such as ? × 7 = 35 and 24 = 6 × ?.
- Real-world: Use classroom packs of pencils to ask, “If 4 packs make 32 pencils, how many pencils are in each pack?”
Plan a lesson for CCSS.Math.Content.3.OA.A.4
Generate a complete lesson plan aligned to this standard, with objectives, activities, and materials. Free, no account needed.
Related standards
- CCSS.Math.Content.5.NF.B.7b
Interpret division of a whole number by a unit fraction, and compute such quotients.
- CCSS.Math.Content.1.OA.D.8
Determine the unknown whole number in an addition or subtraction equation relating three whole numbers.
- CCSS.Math.Content.1.OA.A.2
Solve word problems that call for addition of three whole numbers whose sum is less than or equal to 20, e.g., by using objects, drawings, and equations with a ...
- CCSS.Math.Content.4.NF.B.4
Apply and extend previous understandings of multiplication to multiply a fraction by a whole number.