Scientific Notation
Scientific notation expresses numbers as a coefficient between 1 and 10 multiplied by a power of 10, written in the form c × 10^n. The number 450,000 becomes 4.5 × 10^5, while 0.0032 becomes 3.2 × 10^-3. This system standardizes number representation across all magnitudes, from atomic scales to astronomical distances.
Why it matters
Scientific notation appears throughout science, engineering, and advanced mathematics when dealing with extreme values. Astronomers use it to express distances like 93,000,000 miles (9.3 × 107 miles) from Earth to the Sun. Chemists work with molecular masses such as 6.022 × 1023 particles per mole. Computer scientists measure processing speeds in gigahertz (109 cycles per second). In algebra and calculus, scientific notation simplifies calculations with exponential functions and logarithms. The notation becomes essential in physics courses where students encounter constants like the speed of light (3.0 × 108 meters per second) and Planck's constant (6.626 × 10-34 joule-seconds). Financial modeling also relies on scientific notation for expressing large monetary values in economic equations.
How to solve scientific notation
Scientific Notation
- Write as c × 10n where 1 ≤ c < 10.
- Count decimal places moved = exponent.
- Right = negative exponent, left = positive.
Example: 45000 = 4.5 × 10⁴.
Worked examples
Write 9000 in scientific notation.
Answer: 9 × 103
- Move the decimal point → 9000 = 9 × 103 — Move decimal 3 places left to get 9.
Write 790 in scientific notation.
Answer: 7.9 × 102
- Find coefficient (1 ≤ c < 10) → 790 = 7.9 × 102 — Coefficient is 7.9, exponent is 2.
(3 × 104) × (7 × 102) = _______
Answer: 2.1 × 107
- Multiply coefficients, add exponents → 3 × 7 = 21, 104 × 102 = 106 — Coefficients multiply normally, exponents add.
- Normalize → 2.1 × 107 — Adjust so coefficient is between 1 and 10.
Common mistakes
- Writing coefficients outside the range 1 to 10, such as expressing 2500 as 25 × 10^2 instead of 2.5 × 10^3
- Confusing the sign of exponents when converting decimals, writing 0.004 as 4 × 10^3 instead of 4 × 10^-3
- Adding exponents instead of multiplying coefficients during multiplication, calculating (2 × 10^3) × (3 × 10^4) as 5 × 10^7 instead of 6 × 10^7