Cpp 6: Scientific Notation Review

A Review Of Scientific Notation In Preparation For Floating Points In C++
coding
cplusplus
Author

Tony Phung

Published

September 11, 2025

1. Scentific Notation

Assumptions:

  • Trailing zeros in a whole number with no decimal are not significant

2. Form

  • \([significand]*10^{exponent}\)

2.1 Positive Exponent for larger numbers:

  • \(1.2 \times 10^{4}:\)
    • = \(12,000\) since (\(10^{4}=10,000\))
      • \(1.2\) is the \(significand\)
      • \(4\) is the \(exponent\)
    • using \(e\):
      • = \(1.2e4\)

2.2 Negative Exponent for numbers smaller than 1:

  • \(5e^{-2}\)
    • = \(5 / (10^{2})\)
    • = \(5 / (100)\)
    • = \(0.05\)

3. Significant Digits

Significant Digits are the digits before the \(e\).

3.1 Problem 1: \(600.410\)

  • \(600.410e0\)
  • \(60.0410e1\)
  • \(6.00410e2\)
  • \(6.0041e2 \ [Wrong!]\)
  • \(6.00410e2\)
    • \(6\) significant figures, numbers before \(e\).

Do not trim trailing zeros.
Only trim if there are no decimal places.

3.2 Problem 2: \(0.0078900\)

  • \(0.0078900e0\)
  • \(00.078900e-1\)
  • \(000.78900e-2\)
  • \(0007.8900e-3\)
  • \(7.8900e-3\)

3.3 Problem 3: \(42030\)

  • \(42030e0\)
  • \(4203.0e1\)
  • \(420.30e2\)
  • \(42.030e3\)
  • \(4.203e4\)
    • 4 significant figures

3.4 Problem 4: \(34.50\)

  • \(34.50e0\)
  • \(3.450e1\)
    • 4 sig figs

3.5 Problem 5: \(0.004000\)

  • \(0.004000e0\)
  • \(00.04000e-1\)
  • \(000.4000e-2\)
  • \(0004.000e-3\)
  • \(4.000e-3\)
    • 4 sig figs

3.6 Problem 6: \(123.005\)

  • \(123.005e0\)
  • \(12.3005e1\)
  • \(1.23005e2\)
    • 6 sig figs

3.7 Problem 7: \(146000\)

  • \(146000e0\)
  • \(14600.0e1\)
  • \(1460.00e2\)
  • \(146.000e3\)
  • \(14.6000e4\)
  • \(1.46000e5\)
  • \(1.46e5\)
    • 3 sig figs

3.8 Problem 8: \(146000.001\)

  • \(146000.001e0\)
  • \(14600.0001e1\)
  • \(1460.00001e2\)
  • \(146.000001e3\)
  • \(14.6000001e4\)
  • \(1.46000001e5\)
    • 10 sig figs

3.9 Problem 9: \(0.0000000008\)

  • \(0.0000000008e0\)
  • \(00.000000008e-1\)
  • \(000.00000008e-2\)
  • \(0000.0000008e-3\)
  • \(00000.000008e-4\)
  • \(000000.00008e-5\)
  • \(0000000.0008e-6\)
  • \(00000000.008e-7\)
  • \(000000000.08e-8\)
  • \(0000000000.8e-9\)
  • \(00000000008e-10\)
  • \(8e-10\)
    • 1 sig fig

3.10 Problem 10: \(34500.0\)

  • \(34500.0e0\)
  • \(3450.00e1\)
  • \(345.000e2\)
  • \(34.5000e3\)
  • \(3.45000e4\)
    • 6 sig fig

3.11 Problem 11: \(146000\)

Assume knowledge that zeros are significant:

  • \(146000e0\)
  • \(14600.0e1\)
  • \(1460.00e2\)
  • \(146.000e3\)
  • \(14.6000e4\)
  • \(1.46000e5\)
    • 6 sig figs