Math Core

You have seen the equal sign $=$ many times. But what does it really tell you? It does not mean "the answer comes next." It means the same as.

Think of a balance

Picture a balance scale. Put things on both sides. If both sides hold the same amount, the scale stays level.

The equal sign works just like that. The two sides must be worth the same.

Left side: 🍎 🍎 🍎 · Right side: 🍎 🍎 🍎

Both sides have 3. So $3 = 3$ .

The equal sign means “the same as”

$=$ says the left side and the right side are the same amount.

$4 + 1 = 5$ says "4 plus 1 is the same as 5."

The answer can go on either side

Since both sides are the same, you can flip them around.

$2 + 3 = 5$ and $5 = 2 + 3$ both say the same thing.

Both sides can have math

You can put a sum on each side. Find what each side is worth. Are they the same?

Worked example: A sum on the right

What does $6 = 4 + 2$ mean?

The left side is $6$ . The right side is $4 + 2$ , which is $6$ . So it says "6 is the same as 4 plus 2." ✅

Worked example: Two ways to make 7

What does $5 + 2 = 4 + 3$ mean?

Left side: $5 + 2 = 7$ . Right side: $4 + 3 = 7$ .

Both sides are worth 7. So "5 plus 2 is the same as 4 plus 3." ✅

Worked example: Pick the matching side

Which one is the same as $3 + 5$ : $6 + 1$ or $6 + 2$ ?

$3 + 5 = 8$ . Now check each: $6 + 1 = 7$ and $6 + 2 = 8$ .

So $3 + 5 = 6 + 2$ . Both sides are 8.

Common mistake

Don't read $=$ as "now write the answer." In $5 + 2 = 4 + 3$ , the $4$ is not the answer to $5 + 2$ . Work out both sides, then compare.

Practice

Practice 1

What does the equal sign $=$ mean?

Practice 2

Fill in the number that makes both sides the same.

$9 = 5 + 4$ and $5 + 4 = \square$

Type a number.

Practice 3

What is the right side of $3 + 5 = 6 + 2$ worth?

Type a number.

Practice 4

Which one is the same as $4 + 4$ ?

Practice 5

Which one is the same as $10$ ?

Practice 6

Which one is the same as $9 - 2$ ?

Practice 7

Both sides of $6 + 4 = 8 + 2$ are worth the same number. What number?

Type a number.