“Percent Of” Problems – Easy Way to Solve

• What is 23% of  90?
• 23 is what percent of 90?
• 23 is 90% of what number?

Questions like that prompt many middle schoolers to ask back, “See why I hate math?  Who’s going to remember all the rules for that?”

That’s when I have this big grin on my face and show them the easy way, zero-memorization technique to solve them.

Here’s the technique: The Answer is in the Question, turn English into Math.

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Let’s take the first question: What is 23% of 90?

“What” translates to x (the unknown)

“is” translates to  =  (equal sign)

“of” translates to * (multiply sign)

So,

What is 23%   of 90 becomes:

x       =     .23      * 90

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Do the same for next question:

23   is what percent   of 90 becomes:

23  = x * 90, now just solve for x by dividing 90 on both sides of the equation.

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Isn’t that easy?  The answer is in the question, just translate the question into math symbols.

Now, you try the 3rd question:   23    is 90%   of What number:

When students at our math tutoring center hear this technique, they think it’s magic.  Why is it, when math is easy to understand, kids call them tricks.  Many kids think math is about memorizing a procedure of steps, how sad.  Math is actually one of those subjects that needs the least amount of memorization – when you get it.