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Squaring Numbers
Multiplying Numbers
Dividing Numbers
- any by 0.125
- 2 digits by 1 1/9
- 2 digits by 1 1/8
- 2 digits by 1 1/7
- 2 digits by 1 1/6
- 2 digits by 1 1/5
- 2 digits by 1 1/4
- 2 digits by 1 2/7
- 2 digits by 1 1/3
- 2 digits by 1 2/5
- 2 digits by 1 3/7
- 2 digits by 1 1/2
- 2 digits by 1 3/5
- 2 digits by 1 2/3
- 2 digits by 1 3/4
- 2 digits by 1 4/5
- 2 digits by 2 2/9
- 2 digits by 2 1/4
- 2 digits by 2 1/3
- 2,3 digits by 2 1/2
- 2 digits by 2 2/3
- 2 digits by 2 6/7
- 2 digits by 3 1/8
- 2,3 digits by 3 1/3
- 2 digits by 3 1/2
- 2 digits by 3 4/7
- 2 digits by 4 1/6
- 2 digits by 4 2/7
- 2 digits by 4 4/9
- 2 digits by 4 1/2
- 2 digits by 5
- 2 digits by 5 5/7
- 2 digits by 6 1/4
- 2 digits by 6 2/3
- 2 digits by 7 1/7
- 2 digits by 7 1/2
- 2 digits by 8 1/3
- 2 digits by 8 4/7
- 2 digits by 12 1/2
- 2 digits by 15
- 2,3 digits by 16 2/3
- 2,3 digits by 25
- 2,3 digits by 33 1/3
- 2,3 digits by 35
- 2 digits by 37 1/2
- 2 digits by 40
- 2 digits by 45
- 2 digits by 50
- 2 digits by 62 1/2
- 2 digits by 66 2/3
- 2,3 digits by 75
- 2 digits by 83 1/3
- 2 digits by 87 1/2
- 2 digits by 125
- 2 digits by 166 2/3
- 2 digits by 250
- 2,3 digits by 333 1/3
- 2 digits by 375
- 2 digits by 625
- 2 digits by 875
- 3 digits rep./37+41
- 6 digits rep. by 15873
- 6 digits rep. by 7, then 13
- 6 digits rep. by 13, then 11
- 6 digits rep. by 7,11,13, subtract 101
- 6 digits rep. by 37037 x 5
- mixed numbers by 2
- diff. of squares of 2 consec. 2-digit numbers
- diff. of squares of 2 different 2-digit numbers
- sqrt of squares of 2-digit numbers ending in 1
- sqrt of perfect squares ending in 5
Adding Numbers
Subtracting Numbers
Finding Percents
Calculation
Practice Exercises
Full List
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Dividing a 2- or 3-digit number by 75
- Select a 2-digit number. (Choose larger numbers when you feel sure about the method.)
- Multiply by 4 (or by 2 twice).
- Move the decimal point two places to the left.
- Divide by 3 (express remainder as a fraction).
Example:
- The 2-digit number chosen to divide by 75 is 82.
- Multiply by 4: 4 × 82 = 328.
- Move the decimal point 2 places to the left: 3.28
- Divide by 3: 3.28/3 = 1.09 1/3
- So 82 divided by 75 = 1.09 1/3.
See the pattern?
- The 3-digit number chosen to divide by 75 is 631.
- Multiply by 4 (multiply left to right):
4 × 631 = 2400 + 120 + 4 = 2520 + 4 = 2524.
- Move the decimal point 2 places to the left: 25.24.
- Divide by 3: 25.24/3 = 8.41 1/3
- So 631 divided by 75 = 8.41 1/3.
Practice multiplying left to right so you can do it mentally. You will be able to divide numbers by 75 quickly and accurately.
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