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# Numbers Vocabulary

 add v. to put one number together with another to find the total [eg: 2 + 2 = 4] - addition n. After you've added all the numbers in the column, write the total underneath. arithmetic n. the study of numbers and how to use them, especially for calculating [eg: adding, subtracting, multiplying, dividing] Kelly doesn't need a calculator to do basic arithmetic. She does it in her head. billion n. 1,000,000,000; one thousand million; 109 The only countries with over a billion people in 2019 were India and China. divide v. 2 ÷ 2 [is expressed as] two divided by two - division n. What do you get if you divide thirty by five? equal v. to be the same as [eg: 2 + 2 equals 4] What does 144 divided by 12 equal? giga- prefix meaning one billion [eg: one gigabyte = 1 billion bytes] We used to measure data in kilobytes and megabytes, but now it's more often in gigabytes and terabytes. hundred n. 100; 102 Our family has lived on this land for hundreds of years. kilo- prefix meaning one thousand [eg: one kilogram = 1 thousand grams] - k, K abbr. Did you know that one kilometre equals around point six two of a mile? mega- prefix meaning one million [eg: one megawatt = 1 million watts] - M abbr. Radio station 88.5 FM broadcasts at a frequency of 88.5 megahertz (MHz), or 88,500,000 cycles per second. million n. 1,000,000; one thousand thousand; 106 If you won a million dollars, what would you do with it? minus prep. 5 - 3 [is expressed as] five minus three Five minus three equals two, but three minus five equals minus two. multiply v. 2 x 2 [is expressed as] two multiplied by two - multiplication n. Can you multiply fifteen by sixteen without using a calculator? plus prep. 2 + 2 [is expressed as] two plus two Fifty-two plus nine is sixty-one, isn't it? square v. to multiply a number by the same number [eg: 3 squared = 9, or 32 = 9] If a square with sides that are 12 metres long covers an area of 144 square metres, 12 squared must be 144. square root n. a number that, when multiplied by itself, gives a certain number [eg: the square root of 9 is 3, or √9 = 3] Do you know what the square root of sixteen is? subtract v. to deduct one number from another [eg: 12 minus 3] - subtraction n. To calculate a business's profit, subtract costs and expenses from income. thousand n. 1,000; 103 If we divide a thousand dollars five ways, we get two hundred dollars each, right? times prep. 2 x 2 [is expressed as] two times two - see multiply I know that 7 times 8 equals 56 because we recited multiplication tables at school until we knew them by heart. to the power of multiplication of a number by itself [eg: 2 to the power of 3 (or 2 x 2 x 2) = 8] In arithmetic, "two to the power of three" is written as 23. trillion n. 1,000,000,000,000; a million million; 1012 Six trillion is a 13-figure number consisting of the number six plus twelve zeroes. zero n. 0; oh; nought; nothing A number isn't changed by adding or subtracting zero to or from it.