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Squaring Numbers
Multiplying Numbers
Dividing Numbers
Adding Numbers
- even numbers 2 through selected 2-digit evens
- digits of square of repeating ones
- consecutive odds
- consecutive between 2 numbers
- sequence from 1 to selected 2-digit number
- sequence from 1 to selected 1-digit 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 3-digit 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
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 Subtracting
the squares of two numbers
- Select a 2-digit number and then choose a number two larger or two smaller.
- Multiply the middle number by 4.
Example:
- If the the first number selected is 31:
- Choose 29.
- Multiply the number between them by 4: 4 × 30 = 120
- So (31)(31) - (29)(29) = 120.
See the pattern?
- If the the first number selected is 63:
- Choose 61.
- Multiply the number between them by 4: 4 × 62 = 248
- So 63^2 - 61^2 = 248.
One more:
- If the the first number selected is 73:
- Choose 75.
- Multiply the number between them by 4: 4 × 74 = 296
- So (75x75) - (73x73) = 296.
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