Scientific Notation Calculator
Convert numbers to and from scientific notation (standard form), and perform addition, subtraction, multiplication and division in standard form. Full step-by-step working shown for every operation.
Enter a (coefficient) and n (exponent) for a × 10n
Enter two numbers in scientific notation (a × 10n) and choose an operation.
First number (a × 10n)
Second number (b × 10m)
What Is Scientific Notation? (Standard Form in UK GCSE)
Scientific notation and standard form are the same thing. In the United Kingdom, the GCSE mathematics syllabi — including AQA, Edexcel and OCR — use the term standard form, while the rest of the world (and scientists globally) say scientific notation. Both mean expressing a number as:
where 1 ≤ a < 10 and n is any integer
The rule that the coefficient a must be between 1 (inclusive) and 10 (exclusive) is essential. Without it, you can write the same number in infinitely many ways. With it, every non-zero number has exactly one standard form representation.
Why Do We Need Scientific Notation?
Science, engineering and mathematics constantly encounter numbers that are either astronomically large or vanishingly small. Writing them out in full is error-prone and cumbersome. Consider:
| Ordinary Number | Standard Form | Context |
|---|---|---|
| 602,200,000,000,000,000,000,000 | 6.022 × 1023 | Avogadro's number (mol−1) |
| 299,792,458 | 3 × 108 | Speed of light (m/s, approx.) |
| 149,600,000,000 | 1.496 × 1011 | Earth–Sun distance (m) |
| 0.000000000001 | 1 × 10−12 | One picometre (atomic scale) |
| 0.00000005 | 5 × 10−8 | Typical atomic radius (m) |
| 0.000000001602 | 1.602 × 10−19 | Charge of one electron (C) |
How to Convert a Number to Standard Form
Follow these steps every time:
- Identify the significant figures. Ignore leading zeros and the decimal point position for now.
- Place the decimal point after the first non-zero digit. This gives you the coefficient a, where 1 ≤ a < 10.
- Count how many places you moved the decimal point. Moving left gives a positive exponent; moving right gives a negative exponent.
- Write in the form a × 10n.
Worked Examples
Example 1 — Large number: 45,000
Move the decimal 4 places left: 4.5 × 104
Example 2 — Small number: 0.00073
Move the decimal 4 places right: 7.3 × 10−4
Example 3 — Already between 1 and 10: 6.02
No movement needed: 6.02 × 100
Positive vs Negative Exponents in Standard Form
The sign of the exponent n tells you whether the original number is large or small:
- Positive exponent (n > 0): The number is greater than 1. The larger n, the larger the number. 106 = 1,000,000.
- Zero exponent (n = 0): The number is between 1 and 10 (i.e., 100 = 1).
- Negative exponent (n < 0): The number is between 0 and 1. 10−3 = 0.001.
Students often confuse a negative exponent with a negative number. They are different: 3 × 10−4 = 0.0003 which is positive but small. The number −3 × 104 = −30,000 is negative and large in magnitude.
Multiplying Numbers in Standard Form
Multiplication is the easiest operation in standard form. Use the laws of indices:
Steps: (1) Multiply the coefficients. (2) Add the exponents. (3) Normalise if the new coefficient is not between 1 and 10.
Example: (3.2 × 104) × (5.0 × 103)
Step 1: 3.2 × 5.0 = 16
Step 2: 104 × 103 = 107
Step 3: 16 × 107 → normalise → 1.6 × 108
Dividing Numbers in Standard Form
Steps: (1) Divide the coefficients. (2) Subtract the exponents. (3) Normalise.
Example: (8.4 × 106) ÷ (2.0 × 102)
Step 1: 8.4 ÷ 2.0 = 4.2
Step 2: 106 ÷ 102 = 104
Result: 4.2 × 104 (already normalised)
Adding and Subtracting in Standard Form
Addition and subtraction require the powers of 10 to be equal before you can add or subtract the coefficients. This is analogous to adding fractions with the same denominator.
- Identify the larger exponent.
- Rewrite the number with the smaller exponent so it has the same power of 10 (adjust the coefficient accordingly).
- Add or subtract the coefficients.
- Normalise if necessary.
Example: 3.2 × 104 + 6.0 × 103
Step 1: Larger exponent is 4. Rewrite 6.0 × 103 as 0.6 × 104.
Step 2: 3.2 × 104 + 0.6 × 104 = 3.8 × 104
Result: 3.8 × 104
Standard Form in GCSE Maths (AQA, Edexcel, OCR)
Standard form appears in every UK GCSE Mathematics specification. It typically accounts for 3–6 marks per exam paper. Key skills assessed include:
- Converting between ordinary numbers and standard form
- Ordering numbers given in standard form
- Multiplying and dividing in standard form (without a calculator)
- Adding and subtracting in standard form (both with and without a calculator)
- Interpreting standard form in context (e.g., comparing the size of atoms, planets)
At A-Level, standard form underpins topics including logarithms, exponential functions, and applied science modules. Engineering courses use engineering notation — a variant where the exponent is always a multiple of 3 (e.g., 47,000 = 47 × 103 = 47k), aligning with SI prefixes (kilo, mega, giga, milli, micro, nano).
Scientific Notation on a Calculator
Most scientific calculators display scientific notation using EXP or EE notation. For example, 3.2 × 104 appears as 3.2E4 or 3.2 × 104. Key tips:
- Press EXP (or EE) to enter the exponent — do not type × 10 separately.
- In Excel, enter
3.2E4or use the formula=3.2*10^4. Excel displays it as3.20E+04when cells are formatted as Scientific. - In Python,
3.2e4gives 32000.0;3.2e-4gives 0.00032.