Squaring Numbers
Multiplying Numbers
Dividing Numbers
 any by 0.125
 2 digits by 1 1/9
 2 digits by 1 1/8
 2 digits by 1 1/7
 2 digits by 1 1/6
 2 digits by 1 1/5
 2 digits by 1 1/4
 2 digits by 1 2/7
 2 digits by 1 1/3
 2 digits by 1 2/5
 2 digits by 1 3/7
 2 digits by 1 1/2
 2 digits by 1 3/5
 2 digits by 1 2/3
 2 digits by 1 3/4
 2 digits by 1 4/5
 2 digits by 2 2/9
 2 digits by 2 1/4
 2 digits by 2 1/3
 2,3 digits by 2 1/2
 2 digits by 2 2/3
 2 digits by 2 6/7
 2 digits by 3 1/8
 2,3 digits by 3 1/3
 2 digits by 3 1/2
 2 digits by 3 4/7
 2 digits by 4 1/6
 2 digits by 4 2/7
 2 digits by 4 4/9
 2 digits by 4 1/2
 2 digits by 5
 2 digits by 5 5/7
 2 digits by 6 1/4
 2 digits by 6 2/3
 2 digits by 7 1/7
 2 digits by 7 1/2
 2 digits by 8 1/3
 2 digits by 8 4/7
 2 digits by 12 1/2
 2 digits by 15
 2,3 digits by 16 2/3
 2,3 digits by 25
 2,3 digits by 33 1/3
 2,3 digits by 35
 2 digits by 37 1/2
 2 digits by 40
 2 digits by 45
 2 digits by 50
 2 digits by 62 1/2
 2 digits by 66 2/3
 2,3 digits by 75
 2 digits by 83 1/3
 2 digits by 87 1/2
 2 digits by 125
 2 digits by 166 2/3
 2 digits by 250
 2,3 digits by 333 1/3
 2 digits by 375
 2 digits by 625
 2 digits by 875
 3 digits rep./37+41
 6 digits rep. by 15873
 6 digits rep. by 7, then 13
 6 digits rep. by 13, then 11
 6 digits rep. by 7,11,13, subtract 101
 6 digits rep. by 37037 x 5
 mixed numbers by 2
 diff. of squares of 2 consec. 2digit numbers
 diff. of squares of 2 different 2digit numbers
 sqrt of squares of 2digit numbers ending in 1
 sqrt of perfect squares ending in 5
Adding Numbers
Subtracting Numbers
Finding Percents
Calculation
Practice Exercises
Full List

Dividing a 2 or 3digit number by 3 1/3
 Select a 2 or 3digit number.
 Multiply by 3.
 Move the decimal point one place to the left.
Example:
 The 2digit number chosen to divide by 3 1/3 is 72.
 Multiply by 3: 72 × 3 = 216
 Move the decimal point one place to the left: 21.6
 So 72 divided by 3 1/3 = 21.6.
See the pattern?
 The 2digit number chosen to divide by 3 1/3 is 48.
 Multiply by 3: 48 × 3 = 120 + 24 = 144
 Move the decimal point one place to the left: 14.4
 So 48 divided by 3 1/3 = 14.4.
After practicing, choose larger numbers. Insist on exact answers (you won't get
an exact answer if you divide by 3.3 using a calculator). Multiply from left to right
in steps and impress your friends with your mental powers.
