Maths Shortcut for Squaring Numbers

SQUARING THE NUMBER WHICH ENDS IN 1:
1.     312 =
Ø  First, subtract 1 from the number. The number now ends in zero and should be easy to square. (302  = 3 x 3 x 10 x 10) = 900
Ø  Add 30 and its next number 31 (30+31). We will get 61)
Ø  Add (900 + 61) = 961.

2.     3512=?
Ø  3502 = 122500
Ø  350 +351 = 701
Ø  122500 +701 = 123201

SAME METHOD CAN ALSO BE USED FOR NUMBERS ENDING IN 6.
3.     862 = 
Ø  852 =7225
Ø  85+86 = 171
Ø  7225+171 = 7396

SQUARING THE NUMBER THAT END IN 9 

1.     292 = 
Ø  Add 1 to the number. The number now ends in zero and is easy to square. 
Ø  302 = 900
Ø  Now add 30 with given number29 (30+29 =59)
Ø  Then sub (900 – 59 = 841)

2.     3492 = 
Ø  3502 = 122500
Ø  350+349 = 699
Ø  Sub (122500 – 699 )= 121801