ISO 216

Laws of Indices OCR Module 8 What are Indices? Indices provide a way of writing numbers in a more convenient form Indices is the plural of Index An Index is often referred to as a power For example 5 x 5 x 5 = 53 2 x 2 x 2 x 2 = 24 7 x 7 x 7x 7 x 7 = 75 7 is the BASE NUMBER 5 is the INDEX 75 & 24 are numbers in INDEX FORM Combining numbers 5 x 5 x 5 x 2 x 2 x 2 x 2 = 53 x 24 We can not write this any more simply Can ONLY do that if BASE NUMBERS are the same Rule 1 : Multiplication 26 x 24 = 210 24 x 22 = 26 35 x 37 = 312 General Rule am x an = am+n Rule 2 : Division 26 ? 24 = 32 25 ? 22 = 23 35 ? 37 = 3-2 General Rule am ? an = am-n Rule 3 : Brackets (26)2 = 26 x 26 = 212 (35)3 = 35 x 35 x 35 = 315 General Rule (am)n = am x n Rule 4 : Index of 0