Praxis Core Academic Skills for Educators: Mathematics (5733)Number and QuantityMedium
A financial analyst is evaluating an investment. The value of the investment is 2.5 × 10³ dollars. If a client wants to invest 0.5 times this amount, what is the client's investment in standard notation?
- A$5,000
- B$12,500
- C$125
- D$1,250
Show answer & explanationAnswer & explanation
Correct answer: D. $1,250
First, convert 2.5 × 10³ to standard notation, which is 2,500. Then, multiply this amount by 0.5 to find the client's investment.
Why the other options are wrong
- A. This is 2 times 2,500, or if the original investment was 5.0 x 10^3.
- B. This is 5 times 2,500, or if the original investment was 2.5 x 10^4 and multiplied by 0.5.
- C. This is 0.05 times 2,500.
Scientific Notation to Standard Notation
Scientific notation expresses numbers as a product of a number between 1 and 10 and a power of 10. To convert to standard notation, move the decimal point according to the exponent of 10.
- Positive exponent means move decimal to the right (larger number).
- Negative exponent means move decimal to the left (smaller number).
- The number of places moved equals the absolute value of the exponent.
Memory trick: Exponent positive, decimal right. Exponent negative, decimal left.