Solve 100-(30-21): Order of Operations Practice Problem

Order of Operations with Nested Parentheses

100(3021)= 100-(30-21)=

❤️ Continue Your Math Journey!

We have hundreds of course questions with personalized recommendations + Account 100% premium

Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Solve
00:03 Always solve parentheses first
00:10 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

100(3021)= 100-(30-21)=

2

Step-by-step solution

According to the order of operations, we first solve the exercise within parentheses:

3021=9 30-21=9

Now we obtain:

1009=91 100-9=91

3

Final Answer

91 91

Key Points to Remember

Essential concepts to master this topic
  • PEMDAS Rule: Always solve expressions inside parentheses first
  • Technique: Calculate 30-21=9, then substitute: 100-9=91
  • Check: Verify by working step-by-step: 100-(9)=91 ✓

Common Mistakes

Avoid these frequent errors
  • Working left to right without respecting parentheses
    Don't calculate 100-30=70 first and then subtract 21! This ignores the parentheses and gives 70-21=49, which is completely wrong. Always solve what's inside parentheses before doing any other operations.

Practice Quiz

Test your knowledge with interactive questions

\( 100-(30-21)= \)

FAQ

Everything you need to know about this question

Why can't I just work from left to right like in reading?

+

Math has a special order called PEMDAS (Parentheses, Exponents, Multiplication/Division, Addition/Subtraction). Parentheses always come first - they're like a math container that must be opened before anything else!

What if there are multiple sets of parentheses?

+

Work on the innermost parentheses first, then work your way outward. Think of it like peeling an onion - start from the center and work out layer by layer.

Do I really need to write out each step?

+

Yes! Writing 3021=9 30-21=9 first, then 1009=91 100-9=91 helps you avoid mistakes and makes it easy to check your work.

What's the difference between 100-(30-21) and 100-30-21?

+

Huge difference! 100(3021)=1009=91 100-(30-21) = 100-9 = 91 , but 1003021=7021=49 100-30-21 = 70-21 = 49 . The parentheses change everything!

How can I remember to do parentheses first?

+

Think of parentheses as math's most important rule. They're like a stop sign - you must deal with them before moving on. Practice saying 'Parentheses first!' before starting any problem.

🌟 Unlock Your Math Potential

Get unlimited access to all 18 Commutative, Distributive and Associative Properties questions, detailed video solutions, and personalized progress tracking.

📹

Unlimited Video Solutions

Step-by-step explanations for every problem

📊

Progress Analytics

Track your mastery across all topics

🚫

Ad-Free Learning

Focus on math without distractions

No credit card required • Cancel anytime

More Questions

Click on any question to see the complete solution with step-by-step explanations