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GCSE Number Revision Guide
Master the building blocks of mathematics with our comprehensive guide to Number topics, from basic arithmetic to complex standard form.
Foundation
Higher Tier
Exam Practice
Formulae
Topic Overview
This module covers essential number skills required for both AQA, Edexcel, and OCR examination boards. You will explore the relationships between integers, decimals, and prime numbers, providing a solid foundation for Algebra and Geometry.
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Lessons
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Practice
Worked Examples
BIDMAS & Fundamentals
The Order of Operations
B
Brackets
I
Indices
D
Division
M
Multiplication
A
Addition
S
Subtraction
HCF
Highest Common Factor: The largest number that divides into two or more numbers.
LCM
Lowest Common Multiple: The smallest number that is a multiple of two or more numbers.
Lesson Library
BIDMAS & Arithmetic
Master the order of operations and negative number calculations.
Upper & Lower Bounds
Calculate intervals of error and combined bounds for divisions.
Estimation
Use 1 significant figure to approximate complex calculations.
Factors & Primes
Product of prime factors using trees and Venn diagrams.
HCF & LCM
Strategies for finding common factors and multiples quickly.
Recurring Decimals
Convert repeating decimals to exact algebraic fractions.
Rounding
Significant figures and decimal place precision rules.
Standard Form
Working with very large and small numbers in scientific notation.
Core Subtopics
Structured lessons for every syllabus requirement.
Worked Example
Step-by-Step Walkthrough
THE QUESTION
Work out an estimate for: (42.3 × 9.8) / 0.52
Method
- Round to 1 sig fig
42.3 becomes 40.
9.8 becomes 10.
0.52 becomes 0.5. - Calculate Top Row
40 × 10 = 400 - Final Division
400 / 0.5 = 800
Common Mistake
Students often round 0.52 to 1. This would give 400, which is incorrect estimation for significant figures.
Final Answer
800
Revision Resources
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Topic Quiz
15 Questions
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Related Topics
Frequently Asked Questions
What is the difference between HCF and LCM?
The Highest Common Factor is the largest number that divides evenly into both numbers. The Lowest Common Multiple is the smallest number that both numbers can divide into.
How do I round to 1 significant figure?
Find the first non-zero digit in the number and round it based on the digit immediately to its right.
When do I use Standard Form?
Standard form is used in science and engineering to write very large or very small numbers efficiently as a number between 1 and 10 multiplied by a power of 10.
