Brain Teasers
Threes and Sevens
Using the four digits 3,3,7,7 and the mathematical operators +,-,*,/ write an expression equal to 24. You must use each digit exactly once, but may use each operator multiple times, or not at all. Parentheses are allowed. The following would be a valid expression:
(7 + 3)/(7 + 3) = 1
(7 + 3)/(7 + 3) = 1
Hint
Think fractions.Answer
(3 + 3/7) * 7 = 24Hide Hint Show Hint Hide Answer Show Answer
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Comments
Just for clarity, you don't need to use fractions since 7 divided by four gives you the same answer as the fraction 7/4. Very good problem!
Feb 12, 2002
or you could try:
(7*3)+(7-3)=24
(7*3)+(7-3)=24
Very good problem. I'm sorry Elsie, your answer adds up to 25.
elsie, that's 25
This is one of the best teasers I've seen!
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