Addition

• When adding two-digit numbers, start by adding the ones place digits together.
• 1+1


  2
• 1+3


  4
• 1+4

  5
• 9+1

  10
• 9+2

  11
• 9+3

  12
• 9+4

  13
• 9+5

  14
• 9+6

  15
• 9+7

  16
• 9+8

  17
• 9+9

  18