Algebra | Mini Lesson
Students will use pictures, counters, and number sentences to find missing numbers in simple addition and subtraction equations. The lesson builds early algebra thinking by helping students notice balance and solve for unknowns.
| Term | Definition |
|---|---|
| Equation | A math sentence that shows two sides are equal. |
| Unknown | A missing number we need to find. |
| Balance | When both sides of an equation are the same. |
| Add | To put numbers together. |
| Subtract | To take one number away from another. |
Write 5 + __ = 8 on the board. Ask students what number is missing and how they know.
Think aloud, use fingers or counters, and share possible answers.
Model solving 6 + __ = 10 using counters. Show adding counters to make 10, then state the missing number. Repeat with 9 - __ = 6 using a simple take-away model.
Watch, count along, and repeat the steps with the teacher.
Present 2-3 equations such as __ + 2 = 7, 8 - __ = 5, and 3 + __ = 9. Guide students to solve using counters or drawings.
Solve with a partner, show work on mini whiteboards, and explain how they found the missing number.
Give one final equation for students to solve independently, such as 4 + __ = 11.
Work quietly, write the answer, and hold up their boards for a quick check.
Ask: 'What does the missing number mean in an equation?' Review that the unknown is the number that makes both sides equal.
Answer verbally and restate the key idea.
Review that an unknown is the missing number in an equation and that we can use addition or subtraction to find it.
Students demonstrate understanding by solving one independent missing-number equation and explaining their strategy.
Give students 3 simple missing-number equations to solve at home, such as 2 + __ = 6, 7 - __ = 4, and __ + 5 = 9.