LESSON 4
MULTIPLICATION
Repeated Addition Made Efficient
What is Multiplication?
Multiplication is a fast way of adding the same number many times. Instead of writing 4 + 4 + 4, we can simply write 4 × 3 = 12, meaning three groups of four.
The symbol for multiplication is the times sign (×) or an asterisk (*). The numbers being multiplied are called factors, and the result is called the product.
Multiplication as Repeated Addition
Every multiplication problem can be thought of as repeated addition. 5 × 4 means add 5 four times: 5 + 5 + 5 + 5 = 20. Understanding this connection makes multiplication intuitive.
The Times Tables
Memorizing the times tables (1 through 12) is one of the most important skills in mathematics. It makes all future math faster and easier. Practice them daily until they become automatic.
Multiplying Larger Numbers
To multiply larger numbers, we use long multiplication. Multiply the top number by each digit of the bottom number separately, shifting one place left each time, then add the results.
Properties of Multiplication
Multiplication has key properties: Commutative (a × b = b × a), Associative ((a×b)×c = a×(b×c)), Distributive (a×(b+c) = a×b + a×c), and Identity (a × 1 = a). Any number multiplied by zero equals zero.
Key Facts
The word 'multiply' comes from the Latin 'multiplicare', meaning to fold many times.
Multiplication is commutative — 6 × 9 gives the same result as 9 × 6.
Any number multiplied by zero is always zero — this is called the zero property.
The times tables were used in ancient Babylon over 4,000 years ago, written on clay tablets.