Number Sense - GED Math

1. Write $0.00052$ in scientific notation.

   $5.2 \times 10^{-4}$. The decimal moves $4$ places right, so the exponent is $-4$.

2. What does a negative exponent mean?

   A reciprocal: $a^{-n} = \frac{1}{a^n}$. For example, $2^{-3} = \frac{1}{8}$.

3. Simplify $2^3 \cdot 2^4$.

   $2^7$, which is $128$. When multiplying powers of the same base, add the exponents.

4. Which do you use to find when two repeating schedules next line up: the GCF or the LCM?

   The LCM (least common multiple). The GCF is for splitting things into the largest equal groups.

5. What is the prime factorization of $60$?

   $2^2 \cdot 3 \cdot 5$. $60 = 4 \times 15 = 2 \times 2 \times 3 \times 5$.

6. Simplify $(3^2)^3$.

   $3^6$, which is $729$. When raising a power to a power, multiply the exponents.

7. What is a prime number?

   A whole number greater than $1$ whose only factors are $1$ and itself, such as $2$, $3$, $5$ and $7$.

8. What is the value of any nonzero number raised to the power $0$?

   $1$. For example, $7^0 = 1$.

9. What is the least common multiple of $6$ and $8$?

   $24$. It is the smallest number that both $6$ and $8$ divide into evenly.

10. What is the greatest common factor of $18$ and $24$?

    $6$. It is the largest number that divides both evenly.

11. Order 0.45, $\frac{3}{8}$ and $\frac{1}{2}$ from least to greatest.

    $\frac{3}{8}$, 0.45, $\frac{1}{2}$. As decimals they are 0.375, 0.45 and 0.5.

12. Between which two consecutive whole numbers does $\sqrt{50}$ lie?

    $7$ and $8$, because $7^2 = 49$ and $8^2 = 64$.

Study these flashcards