This is a masterpiece puzzle by the Japanese puzzle inventor Nob Yoshigahara.
The numbers are arranged according to a certain rule. Once you’ve worked out the rule, the missing number can be filled.
| TRIAL METHOD 1 | TRIAL METHOD 2 and Final Solution |
|---|---|
| Start at the top left. How can 72 and 99 make 27? Got it! 99 – 72 = 27. In other words, the number in a circle is the difference of the numbers in the two circles that point to it. And this works down the line with 45 –27 = 18, and 39 – 18 = 21, which means that the missing number must be 15, until you get to 21 – 13 which is equal to 8 not 7! | Back to circle one. How else can 72 and 99 make 27? The answer is so simple it is easy to miss. 7 + 2 + 9 + 9 = 27. The digits all add up. Likewise, 2 + 7 + 4 + 5 = 18, and so the missing number must be 2 + 1 + 3 + 6 = 12. |
Logic Puzzle: If five tigers can catch 5 preys in five minutes, how long will it take one tiger to catch one prey?
Answer: Five minutes.
Using the information, we know it would take one tiger 25 minutes to catch, therefore all 5 prey (5×5=25). Then working backward and dividing 25 by five, we get five minutes for one tiger to catch one prey.
Word Puzzle: Johnny is celebrating his birthday today.Five years ago, Johnny’s age was half of the age he will be in 8 years. How old is he now?
Pattern Guessing: How many total squares are there in this picture?
Riddles: Fix by moving one toothpick to get the answer[Hint: 2 ways ]
Number Puzzle:
What is the weight of each animal?
MATH VOCABULARY CROSSWORD
DOWN
- (1) Number denoting quantity in a set
- (2) Measured in degrees
- (3) Positive, negative and zero numbers
- (4) Triangle with two sides equal
ACROSS
- (5) Number/numeral
- (6) Equivalence/equal
