In a calendar, a square of four numbers is marked. The sum of the numbers is 80. What are the numbers?

Since, the square is composed of 4 numbers,

2 numbers will mark its length, and 2 numbers will mark its breadth.

(as both are equal in square)

Two numbers will be consecutive and the other two numbers will be the same days of the next week (∴ they will also be consecutive)

Let the smallest number be x.

∴ next number = x + 1

Next week, same day

Number will be x + 7

And next number to it = x + 7 + 1 = x + 8

Sum of all the four numbers = 80(given)

⇒ x + x + 1 + x + 7 + x + 8 = 80

⇒ 4x + 16 = 80

⇒ 4x = 80-16

⇒ 4x = 64

⇒

⇒x = 16

x + 1 = 17

x + 7 = 23

x + 8 = 24

Hence, the required numbers are 16,17,23 and 24.