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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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 Finding
55 percent of a number
- Choose a 2-digit number.
- Multiply the number by 11. (Add digits from right to left - see examples).
- Divide by 2.
- Move the decimal point one place to the left.
Example:
- If the number selected is 81:
- Multiply by 11: 11 × 81 = 891
right digit is 1
next digit to left is 1 + 8 = 9
last digit to left is 8
- Divide by 2: 891/2 = 445.5
- Move the decimal point one place to the left: 44.55
- So 55% of 81 = 44.55.
See the pattern?
- If the number selected is 59:
- Multiply by 11: 11 × 59 = 649
right digit is 9
next digit to left is 9 + 5 = 14 (use the 4 and carry 1)
last digit to left is 5 + 1 = 6
- Divide by 2: 649/2 = 324.5
- Move the decimal point one place to the left: 32.45
- So 55% of 59 = 32.45.
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