\( \DeclareMathOperator{cosec}{cosec} \)

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International Baccalaureate Mathematics

Number and Algebra

Syllabus Content

Operations with numbers in the form a × 10k where 1 ≤ a < 10 and k is an integer

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Here are some exam-style questions on this statement:

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Furthermore

Official Guidance, clarification and syllabus links:

Calculator or computer notation is not acceptable. For example, 5.2E30 is not acceptable and should be written as \(5.2 \times 10^{30} \).


If you use the TI-Nspire calculator you can find instructions for entering numbers in standard form on the GDC Essentials page.


Numbers in standard form, also known as scientific notation, are expressed as \( a \times 10^n \), where \( 1 \leq |a| < 10 \) and \( n \) is an integer. This notation is particularly useful when dealing with very large or very small numbers, as it allows for a concise representation.

When performing operations with numbers in standard form, it is crucial to follow the rules of arithmetic carefully. Here are some examples to illustrate the operations:

Addition:

When adding numbers in standard form, it is essential to have the same exponent. If the exponents are different, adjust them appropriately before performing the addition.

$$ (3 \times 10^4) + (5 \times 10^3) = (3 \times 10^4) + (0.5 \times 10^4) \\ = 3.5 \times 10^4 $$

Subtraction:

Similar to addition, when subtracting numbers in standard form, ensure that the exponents are the same before performing the subtraction.

$$ (7 \times 10^6) - (2 \times 10^5) = (7 \times 10^6) - (0.02 \times 10^6) \\ = 6.98 \times 10^6 $$

Multiplication:

When multiplying numbers in standard form, multiply the coefficients (the numbers in front of the power of 10) and then add the exponents of the powers of 10.

$$ (12 \times 10^3) \times (4 \times 10^5) = 48 \times 10^8 $$

Remember to always express your final answer in standard form, ensuring that the coefficient is a number between 1 and 10 (including 1 but excluding 10). Adjust the power of 10 to compensate any changes you have made to the coefficient.

$$= 4.8 \times 10^9 $$

Division:

For division, divide the coefficients and then subtract the exponent in the denominator from the exponent in the numerator.

$$\frac{{3 \times 10^9}}{{6 \times 10^2}} = 0.5 \times 10^7$$

Again remember to always express your final answer in standard form, ensuring that the coefficient is a number between 1 and 10 (including 1 but excluding 10). Adjust the power of 10 to compensate any changes you have made to the coefficient.

$$= 5 \times 10^6$$

This video on Scientific Notation is from Revision Village and is aimed at students taking the IB Maths Standard level course.


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