Math Core

An equation says two sides are the same. But is it telling the truth? You can check! Some equations are true and some are false.

True or false?

Definition

True equation

An equation is true when both sides are worth the same amount. It is false when the two sides are different.

$3 + 1 = 4$ is true. Both sides are 4.

$3 + 1 = 5$ is false. The left side is 4, but the right side is 5.

How to check

Find what the left side is worth.
Find what the right side is worth.
Same number? True. Different? False.

Worked example: A number on the left

Is $7 = 2 + 5$ true or false?

Left side: $7$ . Right side: $2 + 5 = 7$ .

$7$ and $7$ are the same. It is true.

Worked example: Math on both sides

Is $6 + 3 = 5 + 5$ true or false?

Left side: $6 + 3 = 9$ . Right side: $5 + 5 = 10$ .

$9$ and $10$ are different. It is false.

Worked example: Subtraction

Is $10 - 4 = 3 + 3$ true or false?

Left side: $10 - 4 = 6$ . Right side: $3 + 3 = 6$ .

Both sides are 6. It is true.

Common mistake

Some equations look wrong but are true, like $8 = 8$ or $5 = 1 + 4$ . An equation does not need a plus sign on the left. Just check if both sides match.

Tip

Switching the order of numbers you add does not change the sum. So $2 + 9 = 9 + 2$ is always true. You don't even need to add!

Practice

Practice 1

Is $4 + 2 = 6$ true or false?

Practice 2

Is $5 + 3 = 9$ true or false?

Practice 3

Is $8 = 8$ true or false?

Practice 4

Is $7 + 4 = 6 + 4$ true or false?

Practice 5

Is $12 - 2 = 6 + 4$ true or false?

Practice 6

Which equation is true?

Practice 7

Which equation is false?