Operations in scientific notation

2026-11-11Numbers & Estimation Mr Yip

Multiply and divide numbers written as a×10ⁿ and renormalise.

Key formulas

(a×10^m)(b×10^n)=ab×10^{m+n}

What this lesson covers

This lesson builds Secondary 2–3 skill in scientific notation ops. Read the key formulas, study the worked example, then attempt the written practice and the four-question MCQ review.

Method

Write every step. Name the rule you use (scientific notation ops) before substituting numbers. Keep units and signs visible until the final sentence.

Common mistakes

Students often rush the sign, use the wrong percentage base, or cancel terms instead of factors. Pause after each line and ask whether the step is reversible.

Exam habit

Underline the question verb (simplify, solve, factorise, find). Box the final answer and, where sensible, substitute back for a quick check.

Worked example

Worked example — scientific notation ops

Problem. Apply the method for scientific notation ops with the numbers 7 and 4.

Solution. Identify the rule for scientific notation ops. Substitute 7 and 4 carefully with signs in brackets if needed. Complete each operation on a new line. State the final answer clearly and check by reversing one step.

Review quiz

1 / 4

Warm-up on scientific notation ops: what is 5+6?

Practice questions

Practice 1 on scientific notation ops: compute with the value 19.
Practice 2 on scientific notation ops: change the numbers and repeat the same method.
Practice 3 on scientific notation ops: write one sentence explaining the key rule.
Practice 4 on scientific notation ops: invent a similar exam-style question and solve it.

Study notes

What is the main idea of scientific notation ops?

Apply the stated formula or rule with clear steps, then check by reversing or substituting.

How should I revise this topic?

Cover the worked example, redo the practice without notes, then complete the MCQ set and log any wrong options.