Numbers, Dates and Arithmetic PDF

Hassiba Benbouali University of Chlef 2022/2023 Department of Process Engineering/ Department of Mechanical Engineering Technical English Course First course:...

Hassiba Benbouali University of Chlef 2022/2023 Department of Process Engineering/ Department of Mechanical Engineering Technical English Course First course: Numbers, Dates and Arithmetic We use numbers in our day-to-day life. They are often called numerals. Without numbers, we cannot do counting of things, date, time, money, etc. Sometimes these numbers are used for measurement and sometimes they are used for labelling. A number is an arithmetic value used for representing the quantity and used in making calculations. ❖ Cardinal and ordinal numbers A Cardinal Number: are used to talk about the quantity of items (e.g. there are six apples in the bag) so is a number that says how many of something there are, such as one, two, three, four, …. An Ordinal Number: are used to talk about the distribution or order of items (e.g. ‘her apartment was on the third floor’). so that tells the position of something in a list, such as 1st, 2nd, 3rd, 4th, …etc. Most ordinal numbers end in "th" except for: one ⇒ first (1st), two ⇒ second (2nd), three ⇒ third (3rd) Examples: There are four shapes in the row. The yellow circle is the second shape from the left. The green arrow is the fourth shape in the row. The red triangle is the first shape in the row. The pink star is the second shape from the right. The yellow circle is the third shape from the right. Table 1 : Cardinal and Ordinal numbers Cardinal numbers Ordinal numbers 0 zero --- 1 one 1st first 1 Hassiba Benbouali University of Chlef 2022/2023 Department of Process Engineering/ Department of Mechanical Engineering Technical English Course 2 two 2nd second 3 three 3rd third 4 four 4th fourth 5 five 5th fifth 6 six 6th sixth 7 seven 7th seventh 8 eight 8th eighth 9 nine 9th ninth 10 ten 10th tenth 11 eleven 11th eleventh 12 twelve 12th twelfth 13 thirteen 13th thirteenth 14 fourteen 14th fourteenth 15 fifteen 15th fifteenth 16 sixteen 16th sixteenth 17 seventeen 17th seventeenth 18 eighteen 18th eighteenth 19 nineteen 19th nineteenth 20 twenty 20th twentieth 21 twenty-one 21st twenty-first 22 twenty-two 22nd twenty-second 23 twenty-three 23rd twenty-third 30 thirty 30th thirtieth 40 forty 40th fortieth 50 fifty 50th fiftieth 60 sixty 60th sixtieth 70 seventy 70th seventieth 80 eighty 80th eightieth 90 ninety 90th ninetieth 100 a/one hundred 100th a/one hundredth 1,000 a/one thousand 1,000th a/one thousandth 10,000 ten thousand 10,000th ten thousandth 100,000 a/one hundred thousand 100,000th a/one hundred thousandth 1,000,000 a/one million 1,000,000th a/one millionth 1,000,000,000 a/one billion 1,000,000,000th a/one billionth 2 Hassiba Benbouali University of Chlef 2022/2023 Department of Process Engineering/ Department of Mechanical Engineering Technical English Course Be careful with the number 13 and the number 15. While all the other ‘teen’ numbers in English simply add the word ‘teen’ to the regular number (e.g., four-teen, six-teen, seven-teen, nine-teen) 13 uses ‘thir’ and 15 uses ‘fif’. For an added complication, the number 18 only has one ‘t’ (eighteen). even numbers: The numbers which are exactly divisible by 2, are called even numbers. These can be positive or negative integers such as -42, -36, -12, 2, 4, 8 and so on (the number 5,917,624 is even because it ends with a 4). odd Numbers: The numbers which are not exactly divisible by 2, are called odd numbers. These can be both positive and negative integers such as -3, -15, 7, 9, 17, 25 and so on. Odd numbers end in 1, 3, 5, 7, 9. ❖ We have the following number classifications: I. Natural Numbers: are known as counting numbers that contain the positive integers from 1 to infinity. The set of natural numbers is denoted as “N” and it includes N = {1, 2, 3, 4, 5, ……….}. II. Whole Numbers: are known as non-negative integers and it does not include any fractional or decimal part. It is denoted as “W” and the set of whole numbers includes W = {0,1, 2, 3, 4, 5, ……….} III. Integers: are the set of all whole numbers but it includes a negative set of natural numbers also. “Z” represents integers and the set of integers are Z = { -3, -2, -1, 0, 1, 2, 3}. 3 Hassiba Benbouali University of Chlef 2022/2023 Department of Process Engineering/ Department of Mechanical Engineering Technical English Course IV. Rationals Numbers: Any number that can be written as a ratio of one number over another number is written as rational numbers. This means that any number that can be written in the form of p/q. The symbol “Q” represents the rational number. V. Irrational Numbers: The number that cannot be expressed as the ratio of one over another is known as irrational numbers and it is represented by the symbol ”P”. Here is a chart for you to learn how to read the most used math symbols aloud: 4 Hassiba Benbouali University of Chlef 2022/2023 Department of Process Engineering/ Department of Mechanical Engineering Technical English Course ❖ Date: Writing and Saying the Date in British English Rule: Day – Month – Year Writing: 1st February, 2011 Saying: The first of February twenty eleven Writing and Saying the Date in American English Rule: Month – Day – Year Writing: February 1st, 2011 Saying: February first twenty eleven 5 Hassiba Benbouali University of Chlef 2022/2023 Department of Process Engineering/ Department of Mechanical Engineering Technical English Course Format British American A The Fourteenth of March, 2016 March the Fourteenth, 2016 B 14th March 2016 March 14th, 2016 6