Last Minute Review:(check list) Quantitative section Basic mathematic rules and Arithmetic questions: Type of numbers: Natural Numbers the positive integers (whole numbers) 1, 2, 3, etc., and sometimes zero as well. Integers Integers consist of positive natural numbers, their negatives and the number zero. Fraction or decimal values are not considered as integer numbers (…. -3, -2, -1, 0, 1, 2, 3 ....) Rational Numbers A rational number is a number which can be expressed as a ratio of two integers. Non-integer rational numbers (commonly called fractions) are usually written as a/b, where b is not zero. Irrational Numbers An irrational number is any real number that is not a rational number. We cannot express irrational number as fraction a/b, where a and b non-zero. An example of an irrational number is π ≈ 3.141592653589793... Mathematical operations: (+, −, ×, ÷) are the arithmetic operations Besides these operations we have parentheses(brackets). Exponents and Radicals (roots) as well Order of operations: 1. 2. 3. 4. Parentheses (brackets) Exponents or radicals (roots) Division / Multiplication Addition / Subtraction For 3. and 4. we follow the order from left to right Example: Compute 4 − 8 x (3 + 2) + 42 Step 1: first solve parentheses (3+2) = 5 So, 4 – 8 x (3+2) + 42 = 4 – 8 x 5 + 42 Step 2: solve exponent (power) 4 – 8 x 5 + 42 = 4 – 8 x 5 + 16 Step 3: solve multiplication/division 4 – 8 x 5 + 16 = 4 – 40 + 16 Step 4: solve addition and subtraction (from left to right) 4 – 40 + 16 = - 36 + 16 = - 20 ans Composite and Prime number: A composite number is a number with more than 2 factors while a prime number is a number with 2 factors only: 1 and the number itself. A) 2, 3, 5, 7, 11, 13 …. are prime numbers since they are only divisible by themselves B) 4, 6, 8, 9, 10, 12 …. are composite numbers since all of them have multiple factors Example: 1) 121 – 121 is a product of 11 x 11. Since, 121 is divisible by other number besides itself it is not considered as a prime number. It is a composite number 2) 123 – this on the other hand is only divisible by itself so this is a prime number Divisibility: A divisibility test is a rule for determining whether one whole number is divisible by another. It is a quick way to find factors of large numbers. 2 3 The sum of all digits of the given number must be divisible by 3 4 if last two digits of any number are divisible by 4, whole number is divisible by 4 5 Any number that ends with ‘0’ or ‘5’ is divisible by 5 For a number is to be divisible by 6 it must be divisible by both 2 and 3 6 2 Divisibility test The number must be even Example 161 – it is an odd number so it is not divisible by 2. 322 – it is an even number so it is divisible by 2. 134 – 1+3+4=8, since 8 is not divisible by 3,134 isn’t divisible by 3 as well. 882 – 8+8+2=18, as 18 is divisible by 3, 882 is divisible by 3 234 – 34 is not divisible by 4 so 234 isn’t divisible by 4 284 – 84 are divisible by 4 so 284 as whole is divisible by 4 as well 505 – as this number ends with digit 5 it is divisible by 5 162 – it is an even number so it is divisible by 2. 1+6+2 = 9, as 9 is divisible by 3, 162 as whole is divisible by 3 as well. Since, 162 is divisible by both 2 and 3 so, it is divisible by 6 as well. 7 Take the last digit of the number, double it Then subtract the result from the rest of the number If the resulting number is evenly divisible by 7, so is the original number. It is similar to the divisibility test for 4. For a number to be divisible by 8, its last three digits must be divisible by 8 8 9 Its divisibility test is similar to that of 3. The sum of all digits of a number must be divisible by 9. 10 Numbers that end with 0 are divisible by 10 11 Take the alternating sum of the digits in the number, read from left to right. If that is divisible by 11, so is the original number. Rest of the numbers Divisibility tests for numbers after 11 are similar to the rule used to check divisibility of 6 184 – it is an even number so it is divisible by 2, but since 1+8+4 = 13, and 13 is not divisible by 3, 184 is not a multiple of 3 As 184 is divisible by 2 but, not divisible by 3, we cannot divide 184 by 6. 651 – Double of last digit --> 1x2 = 2 65 - (1x2) = 63, as 63 is divisible by 7, 651 as whole is also divisible by 7. 1168 – 16 as well as 8 is divisible by 8 so, 1168 as whole is also divisible by 8. 1227 – this is not divisible by 8 as 227 is not divisible by 8. 189 – 1+8+9=18. Since, 18 is divisible by 9 so 189 is divisible by 9. 277 – 2+7+7 =16. as 16 is not divisible by 9, 277 is not a multiple of 9. 10, 20, 30, 100, 200, 350, 1010 all these are examples of numbers divisible by 10 since, their last digits are 0. 396 – 3 - 9 + 6 = 0, hence 396 is divisible by 11. 3729 – 3 - 7 + 2 – 9 = -11, as –11 is divisible by 11, 3729 is divisible by 11. For example, if we want to check whether a number is divisible by 12 or not. The number must be divisible by 3 and 4 e.g. 264 is divisible by 3 as well as 4 so it is divisible by 12. For example, if we want to check whether a number is divisible by 15 or not. We will have to check the number for its divisibility by 3 and 5 e.g. 255 is divisible by both 3 and 5 so, it is divisible by 15 as well. Using divisibility tests makes it easier to identify factors of any number. This also help us to check whether a number is divisible by other numbers or not. Hence, we can identify prime numbers easily as well. 3 HCF and LCM: HCF: Highest Common Factor - Highest Common Factor (HCF) of two non-zero integers are the largest positive integer that divides both numbers without remainder. LCM: Least Common Multiple - The Least Common Multiple (LCM) of two integers is the smallest positive integer that is a multiple of both numbers. Since it is a multiple, each integer divides it without remainder. If there is no such positive integer, then LCM between the two integers is defined as zero. Fractions: Addition / subtraction of fractions: Steps: 1. 2. 3. 4. 5. The denominators of fractions must be same before we add two or more fractions We take LCM of all denominators We multiply a constant factor with numerator and denominator of each fraction (to obtain equivalent fractions) Now that all fractions have same denominator, the denominator is taken common for all fractions and numerators are added/subtracted Lastly, we can simplify the final fraction by cancellation if possible. Multiplication / Division of fractions: Multiplying fractions: 1. 2. 3. Multiply all numerators together to get numerator of answer Multiply all denominators together to get denominators of answers Simplify the fraction obtained Dividing fractions: 1. 2. 3. 4 Change the division sign to multiplication Take reciprocal of fraction on the right side of division sign Follow same steps as used for multiplication of fractions To simplify calculations while multiplication of fractions we can perform cancellation before multiplying the values of numerators or denominators. Cancellation is only possible between a numerator of denominator (not necessarily of same fraction) Types of fractions: Proper fraction A fraction where numerator is smaller than denominator is known as proper fraction. Proper fraction is always smaller than 1. Improper fraction A fraction where numerator is greater than denominator is known as improper fraction. Improper fraction is always greater than 1. Converting improper fraction to mixed fraction: 5 Mixed fraction Improper fractions can be converted to mixed fractions and vice versa. Converting mixed fraction to improper fraction: 6 Rules to solve: a. Exponents b. Square root 7 _____________________________________________________________________________________ Geometry questions: Angles: TYPES OF ANGLES Complementary angle 8 DESCRIPTION Sum of angles = 90 DIAGRAM Supplementary angle Sum of angles = 180 Corresponding angle Angles with same relative positions are equal Alternate angles Vertical angles 9 If two line intersect opposite angles are equal Properties of shapes: Properties of triangles Area of a triangle: Pythagoras Theorem (used for right angle triangles only) Hypotenuses2 = Base2 + Perpendicular2 h2 = b2 + p2 Special triangles: Type 10 Diagram 30-60-90 degree triangle 45-45-90 degree triangle 3-4-5 triangle 5-12-13 triangle – 11 Angle properties of circle: Perimeter, Area, surface area and volume of 2D and 3D shapes respectively Perimeter: sum of boundaries of any shape Perimeter of circle is known as circumference of the circle. The formula for circumference is 2 pi r Area: space occupied by any 2D shape 12 Surface area and volume of 3D shapes 13 _____________________________________________________________________________________ 14 Algebra questions: Algebraic identities (important) Age related Distance speed time relation Definition: Speed is rate of change of distance. This definition gives us the formula of speed --> Basic formula: Speed=distance/time Now if we rearrange this formula, we get Distance = speed x time And time=distance/speed Make sure to keep these formulae in mind Next, we should know proportionality rules: If we say quantity A is directly proportional to quantity B It means A=KB where K is the constant of proportionality if we say quantity A is inversely proportional to quantity B it means A=K(1/B), where k is constant of proportionality For example: If distance is constant. Then using the formula speed=distance/time, we know that constant distance serves for the value of K the proportionality constant So, if distance is constant speed= distance(1/time) 15 this looks like inverse relationship we say speed is inversely proportional to time in this case Which means if car has more speed it takes less time to convert certain distance, whereas for same distance less speed of car will need more time Similarly, if we say time is constant For example, 2 cars, car A and B cover different distances at different speeds but they take same amount of time to reach the destination we will say that time is constant In this case speed= distance(1/time) 1/time acts as constant So, distance and speed are said to be directly proportional This is an important concept as it is used in many questions even beside speed distance time problems Another important concept related to this section is relative speed: If two objects are travelling in opposite directions their relative speed = sum of speeds of both objects And if they travel in same direction relative speed = difference of both speeds Word problems _____________________________________________________________________________________ Statistical and analytical questions: Pie chart graphs Percentage Data interpretation _____________________________________________________________________________________ 16 Comparison questions: Includes question from all of the above sections