501 Questions To Master GED Test Mathematics_pag52

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501 Questions to Master the GED® Mathematical Reasoning Test
 55. The correct answer is choice c. A number can be written in scien-
tific notation as the product of a number between 1 and 10, including 
1 and excluding 10, and a power of 10. If a number is less than 1, the 
power of 10 is negative. So, to write 0.00231 in scientific notation, 
start at the decimal point and move it to the right until you have one 
non-zero digit to the left of it. You must move the decimal point 
three places to get 2.31, so you multiply that number by 10 to the 
power of –3 because the number 0.00231 is smaller than 1 and you 
moved the decimal point three places to the right. So, in scientific 
notation:
 0.00231 = 2.31 × 10–3
 Choice a is incorrect since this product equals 0.231 (the exponent of 
–3 moves the decimal point to the left three times). 
 Choice b is incorrect since although this product equals 0.00231, the 
first number, 231, is not greater than 1 but less than 10.
 Choice d is incorrect since this is the scientific notation for 2,310 
since the exponent of 3 moves the decimal point to the right three 
times. 
 56. The correct answer is choice d. The distributive property pulls 
the greatest common factor out of a sum or difference of terms and 
represents it as the product of the greatest common factor multiplied 
by the factors of the sum or difference. For example, Ax + Ay is rep-
resented as A(x + y) through the distributive property. Since 8 is the 
greatest common factor of 64 and 8x, the expression 64 – 8x can be 
written as 8(8 – x) or (8 – x)8. 
 Choice a is incorrect because 4 is not the greatest common factor of 
64 and 8x, so this product is not in lowest terms.
 Choices b and c are incorrect because they do not demonstrate the 
distributive property.
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