Year 7: Numeric substitution in simple algebraic expressions

What is Numeric Substitution?

In algebra, we often use letters (like x, y, or a) to represent unknown numbers. Numeric substitution means replacing those letters with actual numbers to evaluate an algebraic expression. It's like filling in the blanks.

Steps for Numeric Substitution

1. Identify the Variable: First, find the letter(s) that represent the unknown numbers.
2. Substitute the Value: Replace each variable with the given number.
3. Simplify: Now you have a regular arithmetic expression. Follow the order of operations (BODMAS/PEMDAS) to simplify it.

Example

Let's say we have the expression: 2x + 3 and we know that x = 4

1. Substitute: Replace x with 4.
2. 2(4) + 3
3. Simplify: 8 + 3 = 11

Therefore, when x = 4, the expression 2x + 3 evaluates to 11.

Practice Makes Perfect! Try substituting different numbers into simple expressions to become comfortable with the process.