• Draw a 3 by 3 square anywhere inside of a monthly view of a calendar.
  
  

• Sum up all the numbers in the 3 by 3 square you drew.
  
  

• What do you notice? What do you wonder?

Here is the answer to this trick

• Draw a  letter T  shape with any 5 numbers in monthly view of a calendar.
  
  

• Sum up the numbers that make up the left and right ends of the T.
  
  

• Sum up the two numbers that make up the bottom of the T.
  
  

• What is the difference between these two sums?
  
  

• What do you notice? What do you wonder?

Here is the answer to this trick