Formulae

=Formulae= Problem Solving Rearranging Subject of formula Substitution Examples of application Direct Proportion
 * Maths
 * Other Subjects

__**Key Objectives (Year 8)**__
 * //Use formulae from mathematics and other subjects//
 * //Substitute integers into simple formulae, including examples that lead to an equation to solve//
 * //Substitute positive integers into expressions involving small powers, e.g. 3x2 + 4 or 2x3 //
 * // Derive algabraic expressions and formulae //

**__Delivery Ideas__**

**Remember key vocabulary:** algebraic expression, equation, formula, partition, multiply out, cubed, square root, to the power of…


 * Show how algebra can be useful in real life.**


 * Make clear the difference between an expression and an equation.**


 * Use letter symbols in different ways and begin to distinguish their different roles.**

For example: In the equation 4 // x // + 3 = 47, // x // is a particular unknown number. In the formula // V // = // IR //, // V // , // I // and // R // are variable quantities, related by the formula.

Numbers can be substitued in place of letters. This can be the case in both expressions and equations.
 * __Substitution__**


 * If a = 4**

What is the value of the expression a + 2

What is the value of the expression 6a

What is the value of the expression 6a + 2


 * __Problem Solving__

Algebra can be used to solve word problems.** //1. On my last birthday I weighed 125 pounds. One year later I have put on x pounds. Which expression gives my weight one year later?//

//a) x 125 b) 125 + x c) x - 125 d) 125x //

__**Rearranging the Subject of Formulae**__

Example:- Rearrange to find c

a = b + c To do this we need to subtract b from both sides of the equation, giving....

a - b = c

Advanced example:- The formula for the area of a circle is //A// = p//r//2. Solve for //r// in the formula. __**

Formulae in Action! (Science)**__ **//V = lbh//** > //**
 * **//the volume V of a cuboid of length l, breadth b and height h : //**
 * **//the surface area S of a cuboid with width w, depth d and height h :


 * //S = 2dw + 2dh + 2hw//**

Speed = Distance ÷ Time Density = Mass (g) ÷ Volume Volume = Height x Length X Width Force (N) = Mass(kg) x Acceleration(m/s 2 ) Amperes(current) = Volts ÷ Ohms(resistance)
 * **//The voltage V in an electrical circuit, with current I and resistance R, is given by the formula: //**
 * //V = IR//**
 * __Useful Links__**

General help [] Balancing equations game []