LOGO Maths YEAR 10 www.themegallery.com Powers and roots Exponentiation求幂: base (a) , power (n) a^n How to read it? Read as: a raised to the n-th power, a raised to the power of n, or possibly a raised to the exponent of n, or more briefly as a to the n. Some exponents have their own pronunciation: for example, a^2 is usually read as a squared and a^3 as a cubed. www.themegallery.com LOGO Example: 5^2=25 (5 raised to the power of 2 equal to 25) 25 is a power of 5, 5 is a root of the power ( square root or perfect square) 4^3=64 ( 4 raised to the power of 3 or 4 cubed) 64 is a cube number. 4 is said to be the cube root of 64 www.themegallery.com LOGO Directed number (integers) Positive Zero Negative Number line can be either horizontal (水平) or vertical (垂直) The rules: ++ makes + -+ makes – - - makes + Sea level (P16) www.themegallery.com LOGO Fractions b/a numerator / denominator Equivalent fractions (equal in value) Simplest form: numerator and denominator have no common factors 90/120=? SIMPLEST FORM www.themegallery.com LOGO Operations on fractions Adding or subtracting fractions:find the LCM of the denominators What is LCM? Lowest common multiple How to find LCM? 2 WAYS 1) list the multiples of each number and then pick out 2) express each of the numbers as a product of prime factors and then work out www.themegallery.com LOGO Continue Dividing fractions reciprocal (multiplicative inverse) The product of reciprocals is always 1 www.themegallery.com LOGO Decimals 5.268 Decimal point: the union end and fractions begin. Changing (transform) fractions to decimals www.themegallery.com LOGO Recurring decimals (Repeating) Dot Recurring decimals are rational numbers (why) www.themegallery.com LOGO Rounding numbers Rounding to the nearest ten Rounding to the nearest unit Rounding to decimal places (e.g. 1 decimal place. 2 decimal places) Rounding to significant figures Work out the answer to one more place than you need. If the extra number is 5 or more, add 1 to the number before it. If the extra number is less than 5, leave the number before it as it is. www.themegallery.com LOGO Significant figures 1,2,3,4,5,6,7,8,9 All non-zero digits are counted as significant figures ZERO (0) ??? Significant or not significant? Zero appearing anywhere between 2 non-zero digits are significant e.g. 100002 Leading zeros are not significant e.g. 0.00052 A zero to the left of a decimal point is significant if there is a non-zero digit to its right. e.g. 10000.02 A zero to the right of a decimal point is significant if there is a non-zero digit to its left. E.g. 120.2300 Zeros in a number not containing a decimal point can be ambiguous e.g. 12000 www.themegallery.com LOGO Ratio and proportion Ratio: a comparision between two or more amounts. Usually expressed as "a to b" or a:b a:b a being the antecedent [ˌæntɪˈsi:dnt] and b being the consequent Hotdogs and pies are sold in a ratio of 3:4 at a local football match. If 840 pies and hotdogs were sold. How many of them were pies? Solution: ①Determine the ratio ( the ratio is 3:4); ②Determine the total number of parts (3+4=7) ③Calculate the value of each part (each part:840/7=120) ④Determine the number of parts needed (Number of pies sold=4×120=480) www.themegallery.com LOGO Map scale The map of Deutschland [ˈdɔitʃlənd] Map scale is 1:1 500 000 This means that 1 unit of measurement on the map must be multiplied by 1 500 000 to get the distance in real life. Express these map scales in the form 1:n 5cm to 2km To do Unit conversion www.themegallery.com LOGO Proportion Show the relationship of two variables whose ratio is constant a and b are proportional if the ratio a/b is constant E.g. Ivan-make a cake. The proportions of sugar or egg is always given Direct proportion Inverse proportion: density Vs. Volume ( certain mass: m=ρ ×V) www.themegallery.com LOGO Rate Rate: compare 2 different quantities that are measure in different units. E.g. velocity =s/t Rate Vs. Proportion Rate: the most common type of rate is "per unit time" which can be expressed as a percentage ( %) Proportion: a:b www.themegallery.com LOGO Percentages Percentage is a fraction that has a denominator of 100 X%=X/100 Percentages of a given quantity E.g. 14% VAT on $100 (in China VAT is 17% or 13%) means if you buy a computer, the price tag says $100, but the store charged you for $114. $14 is VAT( value added tax) VAT=100×(14/100)=14 www.themegallery.com LOGO Profit and loss Make money: the difference between the purchase price and the costs of bringing to market GOAL for businessmen is profit maximization (利润最大化) E.g. the box you made in your economic lesson COST: glue+paper+time=¥1 =$ 0.15 Price:$ 5 Robber!!! www.themegallery.com LOGO Continue Profit=Price-Cost Loss=Cost-Price You buy an air ticket cost $ 1000 Percentage profit Percentage loss www.themegallery.com LOGO Discount Reduced price Pay=original price ×(1discount) www.themegallery.com LOGO Money Foreign currency:Dollar Pound Euro Yen Exchange e.g. $A AUD $100=¥680.98 -> $1=¥6.8098 Cappuccino $5 =?RMB The influence of RMB appreciation www.themegallery.com LOGO Time 12-hour and 24-hour system ante meridiem [ˈænti meˈridiem] (a.m., "before midday") and post meridiem (p.m., "after midday") www.themegallery.com LOGO New words in questions Find the value of Evaluate Work out Express fractions in its simplest form The product of (X) www.themegallery.com LOGO LOGO www.themegallery.com