Trick -1
Addition with 9:
Eg: 9 + 54 = 63
In the above example, 9 is added with 54 and the resultant number is 63. When you add any number (here,54)with 9, the resultant number's(63) unit place(3) will be one number less( 4-1) than the number added to 9 (54) and the tens place(6) will be one number more(5+1)than the number added to 9 (54).