Make the Number 100 - Solution
Make the Number 100 - Solution
The Puzzle: Using the numerals 1,7,7,7 and 7 (a "1" and four "7"s) create the number 100.
As well as the five numerals you can use the usual mathematical operations (+, -, x, and brackets ().
For example: (7+1) (7+7) = 112 would be a good attempt, but not right, because it is not 100.
The Solution . . .
We know of two solutions:
a) 177-77 = 100b) (7+7) (7+(1 7)) = 100
Birthday - Solution
The Puzzle: When asked about his birthday, a man said:
"The day before yesterday I was only 25 and next year I will turn 28."
This is true only one day in a year - when was he born?
The Solution . . .
He was born on December 31st and spoke about it on January 1st.
5-digit Number - Solution
The Puzzle: What 5-digit number has the following features:
If we put the numeral 1 at the beginning, we get a number three times smaller than if we put the numeral 1 at the end of the number.
The Solution . . .
Using an easy equation:
3(100000 + x) = 10x+1
(Why? Well, adding 100000 puts a 1 at the front of a five-digit number, and multiplying by 10 and adding 1 puts a 1 at the end of a number)
Solving this gives:
10x+1 = 3(100000 + x) 10x+1 = 300000 + 3x 10x = 299999 + 3x7x = 299999x= 299999/7 = 42857
The answer is 42857.
Tricky Equation - Solution
The Puzzle: The following equation is wrong: 101 - 102 = 1
Move one numeral to make it correct.
(Caution: Trick)
The Solution . . .
Move the numeral 2 half a line up to achieve 101-102 = 1
Fraction - Solution
The Puzzle: Can you arrange the numerals 1 to 9 (1, 2, 3, 4, 5, 6, 7, 8 and 9) in a single fraction that equals exactly 1/3 (one third)?
Example that doesn't work: 7192/38456 = 0.187
The Solution . . .
5832/17496 = 1/3
Choose the Right Symbol - Solution
The Puzzle: What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?
(Caution: Trick)
The Solution . . .
A Decimal Point
5.9 works nicely
24 from 8,8,3,3 - Solution
The Puzzle: How can I get the answer 24 by only using the numbers 8,8,3,3.
You can use the main signs add, subtract multiply and divide.
(Puzzle supplied by "Steve123")
The Solution . . .
We know of two solutions.
1) Supplied by "mathsyperson":
8/(3-(8/3))=8/(1/3)=24
2) Supplied by "puzzler09", using factorials:
((8 x 3!)/3)+8
= ((8 x 3 x 2 x 1)/3)+8= (48/3)+8= (16)+8= 24
Sum Of Digits is 43 - Solution
The Puzzle: I am thinking of a 6-digit number. The sum of the digits is 43.
And only two of the following three statements about the number are true:
(1) it's a square number,(2) it's a cube number, and(3) the number is under 500000.
.
The Solution . . .
Only Statements 1 and 3 are true. the number is 499849.
7072 = 499849 499849
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