Four hard order of operations problems to tease your brain and blame your math teacher. The first two were were found online and I made up the last two.
Problem #1:
6 ÷2(1 + 2)
This problem was on Facebook and many people got it wrong. According to PEMDAS, The first thing to do is parenthesis.
6 ÷2(1 + 2) = 6 ÷2(3)
Now this is where many people got it wrong. They try to follow PEMDAS by multiplying 2 and 3 to get 6. The problem became 6 ÷ 6 and 6 ÷ 6 = 1
Because the M comes before D, it makes people feel that they have to multiply first.
MD in PEMDAS means to multiply and / or divide from left to right and it does not matter if multiplication is first or not.
The correct way to do it then is to divide 6 by 2 first.
6 ÷2(3) = 3(3) = 9.
Problem #2:
Apparently, many people got it wrong in Japan. What makes this problem hard and tricky? Or is it really?
We need two concepts to solve this problem. First, according to PEMDAS, do division.
Then, you need to know of course how to do this division.
3 ÷ 1/3 = 3 × 3/1 = 9
After that, everything is easy
9 - 9 + 1 = 0 + 1 = 1
Problem #3:
10 × 4 - 2 × (4² ÷ 4) ÷ 2 ÷ 1/2 + 9
= 10 × 4 - 2 × (16 ÷ 4) ÷ 2 ÷ 1/2 + 9
= 10 × 4 - 2 × (4) ÷ 2 ÷ 1/2 + 9
= 10 × 4 - 8 ÷ 2 ÷ 1/2 + 9
= 10 × 4 - 4 ÷ 1/2 + 9
=10 × 4 - 8 + 9
= 40 - 8 + 9
= 32 + 9
= 41
Problem #4:
-10 ÷ (20 ÷ 2² × 5 ÷ 5) × 8 - 2
-10 ÷ (20 ÷ 2² × 5 ÷ 5) × 8 - 2
First stay inside the parenthesis until you get a single number
-10 ÷ (20 ÷ 4 × 5 ÷ 5) × 8 - 2
-10 ÷ (5 × 5 ÷ 5) × 8 - 2 (20 ÷ 4 = 5)
-10 ÷ (25 ÷ 5) × 8 - 2 (5 × 5 = 25)
Now again, resist the urge to do multiplication first and remember that a negative divided by a positive is a negative.
-10 ÷ (5) × 8 - 2
-2 × 8 - 2
-16 - 2
-18
Oct 22, 18 04:14 PM
Take a good look at these optical illusions with geometry
New math lessons
Your email is safe with us. We will only use it to inform you about new math lessons.
Oct 22, 18 04:14 PM
Take a good look at these optical illusions with geometry
Our Top Pages
Formula for percentage
Compatible numbers
Basic math test
Basic math formulas
Types of angles
Math problem solver
Algebra word problems
Surface area of a cube
Finding the average
Scale drawings
Everything you need to prepare for an important exam!
K-12 tests, GED math test, basic math tests, geometry tests, algebra tests.
Real Life Math Skills
Learn about investing money, budgeting your money, paying taxes, mortgage loans, and even the math involved in playing baseball.