3. The hundreds are: C CC CCC CD D DC DCC DCCC DCCCC 100 200 300 400 500 600 700 800 900 4. Thousands are written by placing M before the hundreds. MCC MCCC MCD MD MDC 1400 1500 1600 MC 1100 1200 1300 26. Read the following numbers: XIX; XIV; XXV; XLV; XCIV; XXXV; XLVIII; CCCIV; LXXIX; MDCCCCIX; MDCCCCX; MDC; MDCCIV; LXVIII; XIX; XCIX; CDV. Express the following numbers by the Roman notation: 15; 25; 46; 58; 105; 250; 64; 72; 48; 65; 45; 1150; 1200; 1909; 1906; 1910. 27. The Roman notation is based upon four principles as follows: 1. Repeating a letter, repeats its value. 2. If a letter is placed before one of greater value, its value is to be taken from the value of the greater. 3. If a letter is placed after one of greater value, its value is to be added to that of the greater. 4. If a letter is placed between two letters, eac of greater value, its value is to be taken from thei sum. Note. Comparatively little time should be given to Roma notation, as it is rapidly passing from general use. CHAPTER II ADDITION 28. How many oranges are 3 oranges and 6 oranges? How many apples are 2 apples, 4 apples, and 3 apples? Paid 4 for a pencil, 5¢ for a pad, and 34 for some ink. How much did I pay in all? There are 20 books on the shelf and 4 books on the table. How many books in both places? If you put 4 splints with 6 splints, how many splints will you have? 29. Addition is the process of finding a number equivalent to two or more numbers. 30. The result obtained by addition is called the sum. 31. Only like numbers and units of the same order can be added. 32. The sign of addition is (+). It is called "plus," and means more. Drill Exercises in Addition 33. Give the answers at sight: 34. In writing numbers to be added, we must be careful to place units of the same order under each other. This is done by keeping the figures in units' place under each other, and by using uniform space between the figures of the numbers. If we keep the figures in units' place under each other, we may write dollars and cents or numbers with decimals and add them just as we write and add whole numbers. 1. In the first example shown, the column headed by 5 is in units' place. In the second, the one with U. S. money, the column headed by 4 is in units' place. In the example where decimals are used, the column headed by 2 is in units' place. 2. When the decimal point is used in a number, units' place is always the first place at the left of the decimal point. 3. In addition of decimals, the right-hand figures of the numbers are not always in a vertical column; but the units' column must be vertical and the decimal points stand under each other. 3.462 17.14 8.3465 28.9485 36. In adding, we begin at the right-hand figure, whether adding whole numbers or decimals. If there are more figures than one in the sum of any column, we write the right-hand figure in that column and carry the other figures to the next columns at the left. Business men, in adding long columns of figures, write the numbers carried at the top of the next columns, that they may test their work for any column, knowing what is to be included as "carried over" from the lower column. We test addition by adding the columns both. ways to see if we get the same sum. The sum is always the same kind of units as the numbers added. Only like numbers can be added. |