Understanding Real Numbers - High School Math
Card 0 of 5
Without using a calculator, which of the following is the best estimate for 
?
Without using a calculator, which of the following is the best estimate for
We know that 
and 
.
Because 90 falls is approximately halfway between 81 and 100, the square root of 90 is approximately halfway between 9 and 10, or 9.5.
We know that
Because 90 falls is approximately halfway between 81 and 100, the square root of 90 is approximately halfway between 9 and 10, or 9.5.
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Which of the following are considered real numbers?
Which of the following are considered real numbers?
Real numbers can be found anywhere on a continuous number line ranging from negative infinity to positive infinity; therefore, all of the numbers are real numbers.
Real numbers can be found anywhere on a continuous number line ranging from negative infinity to positive infinity; therefore, all of the numbers are real numbers.
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Place in order from smallest to largest:
Place in order from smallest to largest:
To place in order, first we must find a common denominator and convert all fractions to that denominator.
have a common denominator of 
.
have a common denominator of 
.
have a common denominator of 
.
Therefore we can use common denominators to make all of the fractions look similar. Then the ordering becomes trivial.
To place in order, first we must find a common denominator and convert all fractions to that denominator.
Therefore we can use common denominators to make all of the fractions look similar. Then the ordering becomes trivial.
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What number is 
of 
?
What number is
For percent problems there are verbal cues:
"IS" means equals and "OF" means multiplication.
Then the equation to solve becomes:
For percent problems there are verbal cues:
"IS" means equals and "OF" means multiplication.
Then the equation to solve becomes:
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Which of the following is NOT a real number?
Which of the following is NOT a real number?
We are looking for a number that is not real.
, 
, and 
are irrational numbers, but they are still real.
Then, 
is equivalent to 
by the rules of complex numbers. Thus, it is also real.
That leaves us with: 
which in fact is imaginary (since no real number multiplied by itself yields a negative number) and simplifies to 
.
We are looking for a number that is not real.
Then,
That leaves us with:
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