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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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Add a sequence from one to a selected
2-digit
number
- Choose a 2-digit number.
- Multiply the 2-digit number by half the next number, or
Multiply half the 2-digit number by the next number.
Example:
- If the 2-digit even number selected is 51:
- The next number is 52. Multiply 51 times half of 52.
- 51 × 26: (50 × 20) + (50 × 6) + 1 × 26) =
1000 + 300 + 26 = 1326
- So the sum of all numbers from 1 through 51 is 1326.
See the pattern?
- If the 2-digit even number selected is 34:
- The next number is 35. Multiply half of 34 × 35.
- 17 × 35: (10 × 35) + (7 × 30) + (7 × 5) =
350 + 210 + 35 = 560 + 35 = 595
- So the sum of all numbers from 1 through 34 is 595.
With some multiplication practice you will be able to find these sums of sequential
numbers easily and faster than someone using a calculator!
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