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 even numbers from two through
a
selected 2digit even number
 Divide the even number by 2 (or multiply by 1/2).
 Multiply this result by the next number.
Example:
 If the 2digit even number selected is 24:
 Divide 24 by 2 (24/2 = 12) or multiply by 1/2 (1/2 × 24 = 12).
 The next number is 13; 12 × 13 = 156.
Ways to multiply 13 by 12:
 Square 12, then add 12: 12 × 12 = 144, 144 + 12 = 156.
 Multiply left to right. 12 × 13 can be done in steps: 12 × (10+3) = (12 × 10)
+ (12 × 3) = 120 + 36 = 156.
 So the sum of all the even numbers from two through 24 is 156.
See the pattern?
 If the 2digit even number selected is 42:
 Divide 42 by 2 (42/2 = 21) or multiply by 1/2 (1/2 × 42 = 21).
 The next number is 22; 21 × 22 = 462.
Ways to multiply 22 by 21:
 Square 21, then add 21: 21 × 21 = 441, 441 + 21 = 462.
 Multiply left to right. 21 × 22 can be done in steps: 21 × 22 = (21 × 20) + (21
x 2) = 420 + 42 = 462.
 So the sum of all the even numbers from two through 42 is 462.
