Term
| Right Distributivity of Divsion over addition |
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Definition
Whenever the 3 quotients are whole numbers:
(a+b) / c = (a/c) + (b/c) |
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Term
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Definition
numbers whose sums, differences, products or quotients are easy to calculate mentally.
ex: 86 + 14 = 100; 600/30 = 20 |
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Term
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Definition
| The process of reformulating a sum, difference, product or quotient to one that is more readily obtained mentally. |
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Term
| Additive Compensation (for addition) |
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Definition
Ex: 98 + 59 = 157
+2 -2
100 + 57 = 157 |
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Term
| Equal Compensation (for subtraction) |
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Definition
Ex: 47 - 29 = 18
+1 +1
48 - 30 = 18 |
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Term
| Multiplicative Compensation |
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Definition
Ex: 48 * 5 = 240
/2 *2
24 * 10 = 240 |
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Term
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Definition
Ex: 342 + 136 = 478
300 + 100 = 400
40 + 30 = 70
2 + 6 = 8 |
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Term
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Definition
Ex: 100 * 1000 = 100,000
104 * 105 = 109
20 * 30 = 600 |
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Term
| Multiplying by Special Factors |
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Definition
Numbers such as 5, 25, 99
Ex: 38 * 5 = 190
*2
38 * 10 = 380
/2
190 |
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Term
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Definition
| process of finding an approximate (estimate) to a computation, using mental math |
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Term
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Definition
Using a low value and high value to find a range
EX: 257 + 576 = ?
200 + 500 = 700
300 + 600 = 900
Range is from 700 - 900 |
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Term
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Definition
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Term
| One-Column Front-end Estimation Method |
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Definition
Always provides the low estimate in addition & multiplication
EX: 498 + 251 = ?
400 + 200 = 600 |
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Term
| Two-Column Front-end Estimation Method |
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Definition
Uses the low estimate of the ten's position, a closer estimation
EX: 498 + 251 = ?
490 + 250 = 740 |
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Term
| Front-end with Adjustment |
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Definition
EX: 498 + 251 = ?
400 + 200 = 600
98 + 51 = 100 + 50
750 |
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Term
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Definition
| 3 Types - Range Estimation, One-Column/Two Column |
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Term
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Definition
| EX: 473 rounded down 470; rounded up 480 |
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Term
| Truncate (aka Rounding Down) |
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Definition
"to cut off"
EX: 1276 truncated to 1200 |
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Term
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Definition
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Term
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Definition
| EX: 545 rounded to 540, not 550 (4 is even) |
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Term
| Round to Compatible Numbers |
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Definition
| EX: 26 * 37 -> 25 * 40 = 1000 |
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Term
| Arithmetic Logic - calculators |
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Definition
| the calculator performs operations in the order they are entered |
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Term
| Algebraic Logic - calculators |
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Definition
| the calculator evaluates expressions according to the usual mathematical convection for order of operations |
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Term
| Parentheses - calculators |
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Definition
| used for order of operations in algebraic calculators |
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Term
| Constant Functions - calculators |
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Definition
| repeated operations on calculators |
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Term
| Exponent Keys - calculators |
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Definition
Three common exponenet keys:
x2 = 32 enterd as 3 "x2"
xy = 73 entered as 7 "xy" 3
^ = 73 entered as 7 "^" 3 |
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Term
| Memory Functions - calculators |
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Definition
| stores numbers in calculators memory for future use |
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Term
| Scientific Notation - calculators |
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Definition
| 2.3 x 101 shows as "2.3E1" in calculator |
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