PYHIYP means:
Put your hands in your pockets i.e. use no calculators, no pen & paper; just your eyes and you brain.
The 1st task, a harbinger to be followed by many others, is to prove just by observation and common sense that none of the four numbers listed below is a prime.
i. 5,234,567,896,743
ii. 1,438,525,775,258,341
iii. 77,112,356,378,491
iv. 1,431,436,216,211,339
No time limit!
No cheating!
KISS!
Post your conclusions.
At the outset, striking out the digits that are multiples of 3, we obtain: 52457874
Now, each of 24, 57 and 87 is divisible by 3. So, striking out these 3 two-digit blocks, we obtain: 54, which is divisible by 3.
Consequently, by the Divisibility rule of 3, the given number is a multiple of 3 and therefore cannot be a prime number.
Puzzle Solution: (i)
