Solve the Addition Equation: Finding the Missing Number in 45 + ? = 45

Q: Why isn't the answer 45 since that's the number we see?

Great question! If we used 45, we'd get $ 45 + 45 = 90 $, not 45. We need a number that doesn't change 45, and that's zero!

Q: What is the zero property of addition?

The zero property says that adding zero to any number gives you the same number. For example: $ 7 + 0 = 7 $, $ 100 + 0 = 100 $, and $ 45 + 0 = 45 $.

Q: How do I know when to use zero in addition problems?

Look for patterns where both sides of the equation are the same number. When you see something like $ n + ? = n $, the missing number is always zero!

Q: What if the equation was 45 + ? = 50 instead?

Then you'd subtract: $ 50 - 45 = 5 $. But when both sides are identical like $ 45 + ? = 45 $, zero is always the answer.

Q: Is zero really a number?

Absolutely! Zero is a very important number that represents 'nothing' or 'no amount.' It has special properties in math, like not changing other numbers when you add it.

Addition Equations with Zero Property

$45+?=45$

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations

00:00 Find the unknown

00:04 Any number plus 0 equals the number itself

00:16 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution

Understand the problem

$45+?=45$

Step-by-step solution

To solve this problem, we'll follow these steps:

Step 1: Identify the given equation as $45 + ? = 45$ .
Step 2: Apply the property of zero in addition, which states that adding zero to any number does not change the number.
Step 3: Conclude that the unknown value is zero since $45 + 0 = 45$ .

Therefore, the solution to the problem is $? = 0$ .

Final Answer

Key Points to Remember

Essential concepts to master this topic

Zero Property: Adding zero to any number leaves it unchanged
Technique: Look for equations where both sides are identical: $45 + 0 = 45$
Check: Substitute answer: $45 + 0 = 45$ gives $45 = 45$ ✓

Common Mistakes

Avoid these frequent errors

Assuming the missing number must equal the first number
Don't think the missing number is 45 because 45 + 45 = 90, not 45! This doubles the value instead of keeping it the same. Always use the zero property when both sides of the equation are identical.

Practice Quiz

Test your knowledge with interactive questions

$1\times1000=$

FAQ

Everything you need to know about this question

Why isn't the answer 45 since that's the number we see?

Great question! If we used 45, we'd get $45 + 45 = 90$ , not 45. We need a number that doesn't change 45, and that's zero!

What is the zero property of addition?

The zero property says that adding zero to any number gives you the same number. For example: $7 + 0 = 7$ , $100 + 0 = 100$ , and $45 + 0 = 45$ .

How do I know when to use zero in addition problems?

Look for patterns where both sides of the equation are the same number. When you see something like $n + ? = n$ , the missing number is always zero!

What if the equation was 45 + ? = 50 instead?

Then you'd subtract: $50 - 45 = 5$ . But when both sides are identical like $45 + ? = 45$ , zero is always the answer.

Is zero really a number?

Absolutely! Zero is a very important number that represents 'nothing' or 'no amount.' It has special properties in math, like not changing other numbers when you add it.

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