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Arithmetic with numbers in scientific notation

Arithmetic with numbers in scientific notation

Arithmetic with numbers in scientific notation involves performing basic operations (addition, subtraction, multiplication, and division) on numbers expressed in a specific format that simplifies handling very large or very small values. The general form of scientific notation is:

a×10na \times 10^n

where:

  • aa is a number (the coefficient), typically between 1 and 10,
  • nn is an integer (the exponent), indicating the number of places the decimal moves.

Key Concepts:

  1. Addition and Subtraction:

    • Convert numbers to the same exponent.
    • Adjust the coefficients accordingly.
    • Perform the operation on the coefficients.
    • Normalize the result to proper scientific notation if needed.
  2. Multiplication:

    • Multiply the coefficients.
    • Add the exponents.
    • Normalize the result if necessary.
  3. Division:

    • Divide the coefficients.
    • Subtract the exponent of the divisor from the exponent of the dividend.
    • Normalize the result if needed.

Example:

For multiplication,

(3×104)×(2×103)=(3×2)×104+3=6×107.(3 \times 10^4) \times (2 \times 10^3) = (3 \times 2) \times 10^{4+3} = 6 \times 10^7.

This notation is particularly useful in scientific and engineering contexts, where it allows for easier calculation and clearer representation of extreme values.

Part 1: Multiplying & dividing in scientific notation

In order to simplify multiplication and division using scientific notation, you should multiply and divide numbers with the same base, and add or subtract the exponents. Through this process, complex expressions can be simplified into a single value multiplied with 10 to a certain power. As an example, 7 times 10 to the fifth over 2 times 10 to the negative 2 times 2.5 times 10 to the ninth can be simplified to 1.4 times 10 to the negative 2. Scientific notation helps to simplify complex equations that involve multiplying and dividing numbers with the same base.

When studying "Multiplying and Dividing in Scientific Notation," focus on these key points:

Multiplying in Scientific Notation:

  1. Multiply Coefficients: Multiply the numbers in front (the coefficients).
  2. Add Exponents: Add the exponents of the powers of ten.
  3. Rewrite: Express the result in proper scientific notation (1 ≤ coefficient < 10).

Dividing in Scientific Notation:

  1. Divide Coefficients: Divide the numbers in front (the coefficients).
  2. Subtract Exponents: Subtract the exponent of the denominator from the exponent of the numerator.
  3. Rewrite: Ensure the result is in proper scientific notation (1 ≤ coefficient < 10).

Example:

  • Multiplication: (3 × 10²) × (2 × 10³) = (3 × 2) × 10^(2+3) = 6 × 10⁵
  • Division: (6 × 10⁵) ÷ (2 × 10²) = (6 ÷ 2) × 10^(5-2) = 3 × 10³

Important Notes:

  • Always check if the final answer is in proper scientific notation.
  • Be aware of special cases (like zero coefficients).

Part 2: Multiplying three numbers in scientific notation

Multiplying really big or really small numbers is much easier when using scientific notation. When we multiply numbers in scientific notation, we can commute and associate the factors. That lets us multiply the decimal factors first. Then we can use exponent properties to multiply the powers of 10.

Key Points for Multiplying Three Numbers in Scientific Notation

  1. Understanding Scientific Notation:

    • Numbers are expressed as a×10na \times 10^n where 1a<101 \leq a < 10 and nn is an integer.
  2. Multiplication Process:

    • Multiply the coefficients (the aa parts).
    • Add the exponents (the nn parts).
  3. Example Steps:

    • For numbers (a1×10n1)(a_1 \times 10^{n_1}), (a2×10n2)(a_2 \times 10^{n_2}), and (a3×10n3)(a_3 \times 10^{n_3}):
      1. Compute the product of the coefficients: a1×a2×a3a_1 \times a_2 \times a_3.
      2. Add the exponents: n1+n2+n3n_1 + n_2 + n_3.
  4. Normalization:

    • Ensure the final result is in proper scientific notation (coefficient aa should be between 1 and 10). If necessary, adjust the coefficient and the exponent accordingly.
  5. Final Result:

    • Express the final answer in the form a×10na \times 10^n.

By following these points, you can accurately multiply three numbers in scientific notation.

Part 3: Subtracting in scientific notation

Learn how to subtract numbers written in scientific notation. The problem solved in this video is (4.1 * 10^-2) - (2.6 * 10^-3).

When studying subtracting in scientific notation, focus on these key points:

  1. Ensure Same Power of Ten: Before subtracting, confirm that both numbers are expressed with the same exponent. If not, adjust one or both numbers so they have the same power of ten.

  2. Convert if Necessary: If the exponents are different, convert one number to have the same exponent as the other by adjusting the coefficient and exponent accordingly.

  3. Subtract Coefficients: Once the powers of ten are aligned, subtract the coefficients (the numbers in front).

  4. Maintain the Power of Ten: After the subtraction, keep the power of ten unchanged.

  5. Normalize if Needed: If the resulting coefficient is less than 1 or greater than 10, adjust it by modifying the exponent correspondingly.

  6. Final Expression: Write the final result in proper scientific notation, ensuring that the coefficient is between 1 and 10.

These steps ensure accurate and consistent results when performing subtraction with scientific notation.

Part 4: Simplifying in scientific notation challenge

Let's explore how to simplify expressions with numbers in scientific notation. We'll transform numbers into scientific notation, multiply and divide them, and then reassemble them. It's a cool and useful method for handling large or small numbers!

When studying "Simplifying in Scientific Notation," focus on the following key points:

  1. Understanding Scientific Notation: Familiarize yourself with the format (a × 10^n), where 'a' is a coefficient (1 ≤ a < 10) and 'n' is an integer.

  2. Converting to Scientific Notation: Learn how to convert standard numbers into scientific notation by adjusting the decimal point and applying the appropriate power of ten.

  3. Operations with Scientific Notation:

    • Multiplication: Multiply coefficients and add exponents (a × 10^n × b × 10^m = (a × b) × 10^(n+m)).
    • Division: Divide coefficients and subtract exponents (a × 10^n ÷ b × 10^m = (a ÷ b) × 10^(n-m)).
    • Addition/Subtraction: Convert to like bases, adjust exponents, and then perform the operation.
  4. Simplifying Results: After performing operations, ensure the resulting coefficient is in the proper range (1 ≤ a < 10) and adjust the exponent accordingly if necessary.

  5. Practice Problems: Engage in exercises that require converting, multiplying, dividing, and simplifying to reinforce your understanding.

By mastering these concepts, you will be better equipped to handle challenges in simplifying scientific notation.