Unit 10: Patterns, Sequences, and Early Algebraic Thinking

Day 15 of 30

Solve for unknowns in subtraction

K-2Mathematics

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Learning Objective

I can solve for unknowns in subtraction.

Today's Lesson

Today we will learn how to solve for unknowns in subtraction. Math helps us solve problems and understand the world around us.

Subtraction means taking away from a group to find how many are left. When we see 5 - 2, we start with 5 objects and take away 2. We can count what's left: 3 objects remain. So 5 - 2 = 3. The "-" symbol means "minus" or "subtract." Subtraction is the opposite of addition!

Let's break this down step by step so it's easy to understand. Follow along with the examples, and don't worry if it takes some practice to get the hang of it!

Remember: Making mistakes is part of learning. If something is tricky, try again, look at the examples, or ask for help.

Key Terms
Subtraction

Taking away to find how many are left

Problem

A question we need to solve

Activities
Instructions
1. Use objects or pictures to explore solve for unknowns in subtraction. 2. Try the examples together. 3. Solve practice problems. 4. Check your work.
Materials Needed
  • Counters or objects
  • Pencil
  • Practice sheet
Practice Problems
1

5 - 2 = ___

Hint: Start at 5 and take away 2.
2

8 - 3 = ___

Hint: You can count backward or cross out pictures.
3

There are 6 birds. 2 fly away. How many birds are left?

Hint: Take away the birds that flew away.

Teaching Tip

For younger learners: Use concrete objects and hands-on activities when teaching solve for unknowns in subtraction. Keep sessions short (10-15 minutes) and incorporate movement or songs when possible.

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