How do I know if the exponent is negative?
Numbers smaller than 1 take a negative exponent, numbers 10 or larger take a positive one. Count how many places the decimal point moves to reach a single leading digit.
Convert numbers to and from scientific notation. Perform arithmetic operations with numbers in scientific notation.
Scientific notation = m × 10^n where 1 ≤ |m| < 10. Multiply: (a×10^x)(b×10^y) = ab × 10^(x+y). Divide: subtract exponents.
0.00042 becomes 4.2 × 10⁻⁴ and 93,000,000 becomes 9.3 × 10⁷. Multiplying them gives 39.06 × 10³, normalised to 3.906 × 10⁴.
Numbers smaller than 1 take a negative exponent, numbers 10 or larger take a positive one. Count how many places the decimal point moves to reach a single leading digit.
The calculator-friendly form: 4.2E-4 means 4.2 × 10⁻⁴. Spreadsheets and programming languages use it because superscripts are not available in plain text.
It makes them unambiguous. 4,500 could be two, three or four significant figures, but 4.50 × 10³ clearly states three.