How to Add One Line to Make 100: Answer Revealed

The simple solution to the math challenge taking over TikTok

Co-authored by wikiHow Staff

Last Updated: March 28, 2023 References

Adding One Line to Make 200

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Changing 188 to 200 with One Line

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Changing 9 to 6 with One Line

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Making 5+5+5+5=5555 with One Line

You’ve got to transform two 100s into 200 with just one line. Seems simple, right? Wrong! Even if you’re a math wizard, you might be stumped by this viral riddle, but luckily, we’ve got you covered! In this article, we’re going over how to solve the most popular math riddles using just one line (so you can blow everyone’s mind away).

Method 1

Method 1 of 4:

Adding One Line to Make 200

1
Write a 100 on a blank sheet of paper.
2
Write another 100 directly below the first 100. Make sure both digits are equally spaced and aligned.^{[1]
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3
Draw one short straight line on the top-left “1” to create a “T.” Your new equation should look like "T00 100."^{[2]
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Method 2

Method 2 of 4:

Changing 188 to 200 with One Line

1
Write 188 on a blank sheet of paper.
2
Draw one straight horizontal line directly through the middle of 188.^{[3]
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3
Look at the numbers above and below the horizontal line. By dividing the 188 into 2 parts, it turns into a 100 on top and a 100 on the bottom (100+100=200).

Method 3

Method 3 of 4:

Changing 9 to 6 with One Line

1
Write the Roman numeral 9 (“IX”) on a blank sheet of paper.^{[4]
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2
Draw an “S” at the beginning of “IX.”^{[5]
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3
Read the new expression. With the single line you added, your 9 ("IX") equals a 6 ("SIX").

Method 4

Method 4 of 4:

Making 5+5+5+5=5555 with One Line

1
Write down "5+5+5+5=5555" on a blank sheet of paper.
2
Draw a short straight line to connect the top of the first addition sign to its left side. This transforms the addition sign into a “4” shape.^{[6]
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3
Add up your new equation. Since you transformed the first addition sign into a “4,” your new equation reads “545+5+5=5555.”^{[7]
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