ADDING ONE DIGIT NUMBERS-1a

Example:    5       think of this as 5 pennies  1 1 1 1 1 
         +  4       think of this as 4 pennies  1 1 1 1 
         -----                                  -----------------------
            9                                     1 1 1 1 1 + 1 1 1 1 = 9
or 
            5 +1 = 6
            5 +2 = 7
            5 +3 = 8
            5 +4 = 9
or 
            5 + 5 = 10  so 5 + 4 must be 10 -1 or 9
END