MATHS 1º DE E.S.O IES FERNANDO III CENTRO BILINGÜE

Transcription

1 1º DE E.S.O IES FERNANDO III CENTRO BILINGÜE

2 OUTLINE ASPECTOS LINGÜÍSTICOS VOCABULARY 1 FRACTIONS. 2 ADDING AND SUBTRACTING WITH FRACTIONS NUMBERS ON THE BOTTON ARE THE SAME. NUMBERS ON THE BOTTON ARE NOT THE SAME. 3 MULTIPLYING WITH FRACTIONS. 4.- DIVISION WITH FRACTIONS. 5.- FRACTIONS AND DECIMALS. CONVERTING A FRACTION TO A DECIMAL CONVERTING A DECIMAL INTO A FRACTION 6.- FRACTIONS AND PERCENTAGES CONVERTING A FRACTION TO A PERCENTAGE CONVERTING A PERCENTAGE TO A FRACTION 7.- PERCENTAGES PERCENTAGE INCREASE AND DECREASE 8 - VOCABULARY PRESENT SIMPLE PRESENTE CONTINUO IMPERATIVE LOS PASADOS TO BE THERE WAS THERE WERE. PHONETICS TODAS LAS VOCALES FRACTION ADDING SUBTRACTING MULTIPLYING DIVIDING FRACTION 25

3 1 FRACTIONS. A fraction is an expression, for example: Where the top (numerator) the bottom (denominator) The meaning of the fraction is: is divided by If I have then I select. 2 ADDING AND SUBTRACTING WITH FRACTIONS. WHEN THE NUMBERS ON THE BOTTON ARE THE SAME: All you need to do is add the tops of the fractions together. For example: Sometimes you need to reduce the answer to its simplest form. We divide the top and the bottom by the same number. For example: WHEN THE NUMBERS ON THE BOTTON ARE NOT THE SAME: We use equivalent fractions to create the same denominator. To do this we divide or multiply the numbers on the top and the numbers on the bottom by the same number. The goal is to obtain the same number on the bottom of both fractions. Example: The numbers on the bottom of the fraction is not the same. You can use an equivalent fraction to make the denominator both equal is the smallest number which both 5 and 4 can divide into. That s the Lowest Common Multiple. Now you can add them together 26

4 SUBTRACTING: You subtract using the same methods you used for adding. For example: 3 MULTIPLYING FRACTIONS To multiply fractions, we multiply the top numbers together and multiply the bottom numbers together. For example: 4 DIVIDING FRACTIONS. The rule to remember when dividing fractions is that you flip the fraction you are dividing by upside down, and multiply it by the other fraction. For example: NOTE: Dividing by is the same as multiplying by. Dividing by is the same as multiplying by. 5. FRACTIONS AND DECIMALS A) CONVERTING A FRACTION TO A DECIMAL To change a fraction to a decimal, you divide the top number by the bottom number. (divide the numerator by the denominator). For example: to convert to a decimal, we calculate. There are some fraction/decimal equivalent that you should be familiar with 27

5 B) CONVERTING A DECIMAL INTO A FRACTION If the decimal terminates (ends), the denominator will be 10, or 100, or 1000, depending on the number of decimal places. five tenths 45 hundredths nine twentieths 240 thousandths = six twenty-fifths If the decimal repeats with a single digit, de denominator will be 9: If the decimal repeats with two digits, the denominator will be 99: 6 FRACTIONS AND PERCENTAGES. A) CONVERTING A FRACTION TO A PERCENTAGE. To change a fraction to a percentage, multiply it by 100. For example: B) CONVERTING A PERCENTAGE TO A FRACTION. To change a percentage to a fraction, divide by 100. For example: 7.- PERCENTAGES Per cent means out of 100. If 90 per cent of the populations owns a mobile phone, this means 90 out of every 100 people have one. (Per cent =%) In real life (and maths) we find a percentage of a quantity, not just out of 100. For example 30% of 200. First write the percentage as a fraction or a decimal, 28

6 Then multiply by the quantity Problem: Ann is buying a pair of jeans. The original price was 75 but there is a discount of 30%. How much will the discount be? Answer: Discount: 30% of 75 If the question is for the discount price, we subtract the discount from the original price Problem: A car cost before IVA (VAT: Value Added Tax) Find the cost of the IVA if it is charged at 17 5%. 17 5% of We round to two decimal places. PERCENTAGE INCREASE AND DECREASE. In some questions you have the cost price and the selling prices and have to find the percentage increase or decrease. We need to find one amount as a percentage of another. To do this, You form a fraction from the two amounts and multiply this by 100. Example: Ann buys a radio for 45 and sells it for 63. What is his percentage profit? Answer: The cost price is 45, the selling price is 63. The profit is. To calculate the percentage profit you have to find what the profit is as a percentage of the original price. So divide the profit by the original price and multiply by 100. Example: Lucas buys a coat in a sale for 30. The original cost of the coat was 60. What is the percentage decrease?. Answer: The coat cost 30. The original price was 60. The decrease is 60-30=30. To calculate the percentage decrease, divide the actual decrease by the original price and multiply by

7 8.- VOCABULARY English Pronunciation Spanish Add /æd/ Sumar Amount /ə'maʊnt/ Cantidad Bottom /'bɑ:təm / /'bɒtəm/ Abajo Decimal /'desɪməl/ Decimal Decrease /dɪ'kri:s/ Descenso Denominator /dɪ'nɑ:məneɪtər / Denominador Divide /də'vaɪd / Dividir Equivalent /ɪ'kwɪvələnt/ Equivalente Fractions / 'frækʃən/ Fracción Increase /ɪn'kri:s/ Aumento Multiply /'mʌltəplaɪ/ Multiplicar Numerator /ˈnjüməˌreɪtər/ Nunerador Percentage /pə'sentɪdʒ/ Porcentaje Profit /'prɒfɪt/ Ganancias Quantity /'kwɑ:ntəti / Cantidad Subtract /səb'trækt/ Restar Top /top/ Arriba 30