Essential GMAT Quant Skills Flashcards
Proper fractions are what?
Numerator is less than denominator
Improper fractions are…
When the numerator is greater thsn the denominator
What is the LCD?
The smallest whole number that is divisible by each of the denominators
What are equivalent fractions?
Two fractions that appear to be different but are the same value
Two fractions are equivalent fractions if…
a/b = c/d if axd=cxb
What do you do in cross simplifications?
When multiplying two fractions, you take the numerator of one fraction and the denominator of the other and divide both by the same number
What is the reciprocal of a number?
One over the number
What is the reciprocal of 1？
1
What is the reciprocal of -1?
-1
What is the reciprocal of 0?
0 doesn’t have a reciprocal
What is the product of a number and its reciprocal?
1
What are complex fractions?
Fractions whose numerator, denominator or both are also fractions
What is the bow tie method used for?
To compare size of fractions
What is the bow tie method?
Given a/b and c/d, a/b is larger than c/d if axd is larger than cxb
What are some ways to compare fraction size?
- Using a reference point to compare the size of fractions (best used to determine the smallest or largest fraction in a set)
- The bow tie method
- Using a common denominator
- Using a common numerator
What are some ways to compare fraction size?
- Using a reference point to compare the size of fractions (best used to determine the smallest or largest fraction in a set)
- The bow tie method
- Using a common denominator
- Using a common numerator
How can you compare fraction size using a common numerator?
When all the fractions in a set have the same numerator, the larger the denominator, the smaller the fraction is
What happens if you add a positive constant to both numerator and denominator of a fraction that is between 0 and 1?
It will become larger
What happens if you add a positive constant to both numerator and denominator of a fraction that is larger than 1?
It will become smaller
What happens if you subtract a positive constant to both numerator and denominator of a fraction that is between 0 and 1?
It will become smaller as long as the resulting fraction is still positive
What happens if you subtract a positive constant to both numerator and denominator of a fraction that is larger than 1?
It will become larger as long as the resulting fraction is still positive
How do you multiply decimals?
- Ignore decimal point and multiply
- Count total number of decimal places to the right of the decimal point in both the numbers multiplied
- Move the decimal point to the left that same amount of spaces
What is a shortcut for multiplying decimals?
Count the number of decimal places both numbers have and that will allow you to eliminate the answer choices that don’t have that number.
Be careful with multiplications that end in 0 because the answer choice won’t show the ending 0
How do you divide decimals?
- Move the decimal point of the divisor to the right until it becomes a whole number
- Move the decimal point of the dividend by the same number of places
- Divide using long division
How do you compare decimals?
You compare them place by place starting at the tenths place
Can you convert non-terminating and non-repeating decimals to fractions?
No
Decimal table of 1/6
1/6 | 0.143
2/6 | 0.333
3/6 | 0.50
4/6 | 0.667
5/6 | 0.833
Decimal table of 1/7
1/7 | 0.143
2/7 | 0.286
3/7 | 0.429
4/7 | 0.571
5/7 | 0.714
6/7 | 0.857
Decimal table of 1/8
1/8 | 0.125
2/8 | 0.25
3/8 | 0.375
4/8 | 0.50
5/8 | 0.625
6/8 | 0.75
7/8 | 0.875
What is the order of the square root and square of a number between 0 and 1?
X^2 < x < square root x
Perfect squares never end in what numbers?
2, 3, 7, 8
