Squaring Numbers
 beginning with 1
 beginning with 5
 beginning with 9
 ending in 1
 ending in 2
 ending in 3
 ending in 4
 ending in 5
 ending in 6
 ending in 7
 ending in 8
 ending in 9
 made up of 1's
 made up of 3's
 made up of 6's
 made up of 9's
 in the 20's
 in the 30's
 in the 40's
 in the 50's
 in the 60's
 in the 70's
 in the 80's
 in the 100's
 in the 200's
 in the 300's
 in the 400's
 in the 500's
 in the 600's
 in the 700's
 between 800810
 in the 900's
 between 10001100
 between 20002099
 between 30003099
 between 40004099
 between 50005099
 between 60006099
 between 70007099
 3's and final 1
 3's and final 2
 3's and final 4
 3's and final 5
 3's and final 6
 3's and final 7
 3's and final 8
 3's and final 9
 6's and final 1
 6's and final 2
 6's and final 3
 6's and final 4
 6's and final 5
 6's and final 7
 6's and final 8
 6's and final 9
 9's and final 1
 9's and final 2
 9's and final 3
 9's and final 4
 9's and final 5
 9's and final 6
 9's and final 7
 9's and final 8
 1 and repeating 3's
 1 and repeating 6's
 1 and repeating 9's
 2 and repeating 3's
 2 and repeating 6's
 2 and repeating 9's
 3 and repeating 6's
 3 and repeating 9's
 4 and repeating 3's
 4 and repeating 6's
 4 and repeating 9's
 5 and repeating 3's
 5 and repeating 6's
 5 and repeating 9's
 6 and repeating 3's
 6 and repeating 9's
 7 and repeating 3's
 7 and repeating 6's
 7 and repeating 9's
 8 and repeating 3's
 8 and repeating 9's
 9 and repeating 3's
 9 and repeating 6's
 6digits repeating
 2 rep./sq. of 1 digit
Multiplying Numbers
Dividing Numbers
Adding Numbers
Subtracting Numbers
Finding Percents
Calculation
Practice Exercises
Full List

Squaring a 2digit number ending in 9
 Choose a 2digit number ending in 9.
 The last digit of the answer is always 1: _ _ _ 1
 Multiply the first digit by 8 and add 8 (keep the carry): _ _ X _
 Multiply the first digit by the next consecutive number and
add the carry: the product is the first two
digits: XX _ _.
Example:
 If the number is 39:
 The last digit of the answer is 1: _ _ _ 1
 Multiply the first digit (3) by 8 and add 8 (keep the
carry): 8 × 3 = 24, 24 + 8 = 32; the next digit of
the answer is 2 (keep carry 3): _ _ 2 1
 Multiply the first digit (3) by the next number (4)
and add the carry (3): 3 × 4 = 12, 12 + 3 = 15
(the first two digits): 1 5 _ _
 So 39 × 39 = 1521.
See the pattern?
 For 79 × 79
 The last digit of the answer is 1: _ _ _ 1
 Multiply the first digit (7) by 8 and add 8 (keep the
carry): 8 × 7 = 56, 56 + 8 = 64; the next digit of
the answer is 4 (keep carry 6): _ _ 4 1
 Multiply the first digit (7) by the next number (8)
and add the carry (6): 7 × 8 = 56, 56 + 6 = 62
(the first two digits): 6 2 _ _
 So 79 × 79 = 6241.
Practice other examples using this pattern, and in no time you'll be able
to give these squares faster than someone using a calculator.
