Squaring Numbers
Multiplying Numbers
Dividing Numbers
Adding Numbers
 even numbers 2 through selected 2digit evens
 digits of square of repeating ones
 consecutive odds
 consecutive between 2 numbers
 sequence from 1 to selected 2digit number
 sequence from 1 to selected 1digit number and back
 sequences in the 10's
 sequences in the 20's
 sequences in the 30's
 sequences in the 40's
 sequences in the 50's
 sequences in the 60's
 sequences in the 70's
 sequences in the 80's
 series of doubles
 series of quadruples
 series of 10 numbers
Subtracting Numbers
 1's repeating, divide by 9, subtract 21
 8's repeating, divide by 9, subtract 10
 squares of two numbers
 reversing/adding/subtracting 3digit numbers
Percents
 finding 2.5 percent
 finding 5 percent
 finding 15 percent
 finding 20 percent
 finding 25 percent
 finding 33 1/3 percent
 finding 40 percent
 finding 45 percent
 finding 55 percent
 finding 60 percent
 finding 70 percent
 finding 75 percent
Calculation
Practice Exercises
Full List

Adding a sequence of consecutive odd numbers
 Choose a 2digit odd number. Add all the odd numbers starting with one through
this 2digit number:
 Add one to the 2digit number.
 Divide this sum by 2 (take half of it).
 Square this number. This is the sum of all odd numbers from 1 through the 2digit
number chosen.
Example:
 If the 2digit odd number selected is 35:
 35+1 = 36 (add 1).
 36/2 = 18 (divide by 2) or 1/2 × 36 = 18 (multiply by 1/2).
 18 × 18 = 324 (square 18): 18 × 18 = (20  2)(18) = (20 × 18)  (2 × 18) = 360
 36 = 360  30  6 = 324.
 So the sum of all the odd numbers from one through 35 is 324.
See the pattern?
 If the 2digit odd number selected is 79:
 79+1 = 80 (add 1).
 80/2 = 40 (divide by 2) or 1/2 × 80 = 40 (multiply by 1/2).
 40 × 40 = 1600 (square 40).
 So the sum of all the odd numbers from one through 79 is 1600.
