The equal sign tells us that two sides have the same amount. It does not mean that the answer always comes after it. When we write 3 + 2 = 5, we are saying that 3 plus 2 is the same amount as 5.
A balance scale is a helpful picture because it stays level when both sides are equal.
Think of the left side and right side of an equation as two pans on a scale. If the left pan has 3 red apples and 2 blue apples, it has 5 apples in all. If the right pan has 5 apples, the scale balances because both sides show the same amount.
This also means 5 = 3 + 2 is true, because the same amounts are still on both sides.
Key Facts
- The equal sign = means is the same amount as.
- 3 + 2 = 5 means 3 plus 2 is the same amount as 5.
- 5 = 3 + 2 is also true because both sides have the same amount.
- A level balance scale shows equality.
- If both sides of an equation match in amount, the equation is true.
- If one side has more or less than the other, the equation is not equal.
Vocabulary
- Equal sign
- The symbol = that means two amounts are the same.
- Equation
- A number sentence that shows two amounts are equal.
- Same amount
- Two groups have the same number of objects or the same value.
- Balance scale
- A tool with two sides that can show whether amounts are the same.
- Add
- To put amounts together to find how many there are in all.
Common Mistakes to Avoid
- Thinking = means the answer comes next. This is wrong because = means both sides have the same amount, no matter which side the answer is on.
- Saying 5 = 3 + 2 is backwards and wrong. This is wrong because 5 and 3 + 2 are the same amount, so the equation is true.
- Only counting one color of apples in 3 red apples + 2 blue apples. This is wrong because all apples count, so there are 5 apples in all.
- Writing 3 + 2 = 4 because there are two numbers being added. This is wrong because you must count the total amount, and 3 plus 2 makes 5.
Practice Questions
- 1 There are 4 stars on the left side of a scale and 4 stars on the right side. Write an equation using = to show the amounts are the same.
- 2 Fill in the missing number: 2 + 3 = __. Then write the same equation with 5 on the left side.
- 3 A scale has 1 apple and 4 apples on the left pan, and 5 apples on the right pan. Explain why the scale is level using the meaning of the equal sign.