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Verifying Addition Statements

This lesson shows how to verify addition statements with numbers up to 20 by working out both sides of an equation and comparing them. Students learn to spot true and false addition equations, fix incorrect ones, and check statements with an addend or sum on either side of the equal sign.

What Does It Mean to Verify an Addition Statement?

An addition statement is a complete equation, such as \( 7 + 5 = 12 \). It has two sides connected by an equal sign. Verifying an addition statement means checking whether both sides really do have the same value. If they match, the statement is true. If they do not match, the statement is false.

Sometimes an addition statement has numbers added on both sides of the equal sign, like \( 3 + 4 = 2 + 5 \). Verifying this kind of statement means finding the sum on each side and comparing the two results, not just looking at the numbers.

Steps to Verify an Addition Statement

To check whether an addition statement is true or false, follow these steps.

Find the value of the left side of the equal sign.
Find the value of the right side of the equal sign.
Compare the two values.
If the values are the same, the statement is true. If they are different, the statement is false.

You can use any strategy you already know to work out each side, such as counting, a number line, or addition facts you have memorized. The strategy does not matter as much as making sure you compute each side carefully before comparing.

Example: Checking a Simple Statement

Is \( 9 + 6 = 15 \) true or false?

The left side is \( 9 + 6 \), which equals 15. The right side is just 15. Since both sides equal 15, the statement is true.

Example: Finding a False Statement

Is \( 8 + 6 = 13 \) true or false?

The left side is \( 8 + 6 \), which equals 14. The right side is 13. Since 14 does not equal 13, the statement is false. The correct statement would be \( 8 + 6 = 14 \).

Three addition statements checked for truth by comparing both sides.

Example: Checking a Statement with Addition on Both Sides

Is \( 4 + 7 = 5 + 6 \) true or false?

Work out each side on its own. The left side, \( 4 + 7 \), equals 11. The right side, \( 5 + 6 \), also equals 11. Since both sides equal 11, the statement is true, even though the two sides use different numbers.

Why This Skill Matters

Verifying addition statements builds the habit of checking work carefully instead of assuming an answer is correct. It also strengthens the idea that the equal sign means "the same value as," not just "here comes the answer." This understanding supports later skills like adding with 3 numbers up to 20 and other strategies for adding with digits up to 20, since students need to check their sums are reasonable at every step.

Common Mistakes to Watch For

Assuming a statement is true just because the numbers look similar, without actually adding.
Adding only one side and forgetting to check the other side of the equal sign.
Making a small counting error, which turns a true statement into a false one.
Forgetting to fix a false statement by writing the correct sum.

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Math 1