3.5.D

Math3rd Grade

The Standard

determine the unknown whole number in a multiplication or division equation relating three whole numbers when the unknown is either a missing factor or product

Texas Essential Knowledge and Skills for Mathematics

Teacher's field guide

What This Standard Means

What Students Need to Do

Students find a missing number in a multiplication or division equation. They decide whether the unknown represents the total, the number of groups, or the amount in each group.

What Mastery Looks Like

Students accurately solve equations such as 7 × __ = 56 and __ ÷ 6 = 8. They use related multiplication and division facts to check each answer.

Common Misconceptions

Students may multiply every pair of numbers they see, even when they need to divide. They may confuse the unknown product with an unknown group size or number of groups.

How to Assess It

Give an exit ticket with 6 × __ = 42, __ × 8 = 32, and 45 ÷ 5 = __. Ask students to solve and show one related fact.

Lesson moves

Ways to Teach It

  1. Use counters and cups to model 24 objects split into unknown groups, then write the matching multiplication and division equations.

  2. Ask students to explain how 6 × __ = 42 and 42 ÷ 6 = __ are related.

  3. Play Missing Number Match with cards showing equations, answers, and related fact families for students to pair.

  4. Present a packing problem with equal boxes and items, then have students find the missing total, box count, or items per box.

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