Triangular Number Sequence

• Find the difference between the 2nd and 7th triangular numbers?

  25
• Daisy lists some consecutive triangular numbers : 210 231 253 276 . Find the triangular number before 210

  190
• Daisy lists some triangular numbers : 210 231 253 276 . Find out the number after 276 ?

  300
• What happens if you add 2 consecutive square numbers?

  You get square numbers
• There are 5 people in a room. Everybody shakes hands with each other once. How many handshakes are there in total?


  10
• Find the 50th triangular number : use the rule n(n+1) / 2

  1275