Today’s puzzle reminds me of a pair of glasses. If I misplace my glasses, it can be difficult to find them, because I can’t see well without them. But it shouldn’t be hard to see the logic in this level 4 puzzle. Give it a try. I think you will be pleasantly surprised.

Print the puzzles or type the solution in this excel file: 10-factors-1148-1160

Now let me see what I can tell you about the number 1153:

1153 is the sum of the thirteen prime numbers from 61 to 113.

Like every other prime number ending in 52, it is the sum of two squares:

33² + 8² = 1153

1153 is the hypotenuse of a Pythagorean triple:

528-1025-1153 calculated from 2(33)(8), 33² – 8², 33² + 8²

1153 is a palindrome in two other bases:

It’s 5C5 in BASE 14 (C is 12 base 10) because 5(14²) + 12(14) + 5(1) = 1153,

and 141 in BASE 32 because 32² + 4(32) + 1 = 1153