The dollar sign is $; the sign for cent or cents is ¢.

25. Since 10 units of one denomination make 1 unit of the next higher denomination, United States money is conveniently represented in figures by the decimal system, dimes and cents being written as hundredths, and mills as thousandths of a dollar, which is the unit of the system.

Thus, 4 eagles, 6 dollars, 7 dimes, 8 cents, 5 mills, is written $46.785, and read "46 dollars, 78 cents, 5 mills."

Also, $.01 is read "1 cent"; $.001, "1 mill"; $.256, "25 cents 6 mills"; 25, "25 cents"; and 56.7 %, "56 and 7 tenths cents."

26. In business, the seller usually regards any part of a cent as an additional cent.

3. Write in the decimal form, using the sign $:

19 dollars 7 cents

63 dollars 82 cents

80 cents; 1 cent 5 mills

4. Write to the nearest cent:

500 dollars 16 cents 3 mills

88 dollars 37 cents 5 mills 740 cents; 23,765 cents $1.667; $.264; $4.56; $.812.

ROMAN SYSTEM

28. The Roman notation uses seven letters, namely:

29. These letters are combined to represent other numbers according to the following principles :

1. When a letter is followed by the same letter or a letter of less value, the values of the letters are to be united.

Thus, II represents 2; XXX, 30; VI, 6; DC, 600.

2. When a letter is followed by a letter of greater value, its value is to be taken from that of the greater.

Thus, IV represents 4; IX, 9; XL, 40; CD, 400.

3. A letter with a bar placed over it represents a thousand times as much as it does without the bar.

Thus, V represents 5000; X, 10,000; IV, 4000.

30. This table further illustrates the method of combination: III, 3 XIV, 14 XLI, 41

XCIX, 99

MC, 1100

FUNDAMENTAL PROCESSES

32. You have learned how to add, subtract, multiply, and divide, but you should practice on these operations until you can perform them rapidly and with absolute accuracy.

ADDITION OF INTEGERS AND DECIMALS

33. The process of finding a number that is equal to two or more given numbers is called addition.

34. The result obtained by adding is called the sum, or

amount.

35. The numbers added are called addends.

36. The sign + indicates addition and is read plus.

37. The sign = indicates equality and is read equals, or is equal to.

38. Numbers that are made up of the same kind of units are called like numbers.

$4 and $6 are like numbers; also 8 feet and 5 feet.

39. Numbers that are made up of different kinds of units are called unlike numbers.

7 pounds and 9 gallons are unlike numbers.

40. 1. Can you add $4 and $6? 7 pounds and 9 gallons? Only like numbers can be added.

2. What is the sum of 6 and 2? of 2 and 6? of 3, 4, and 2? of 2, 4, and 3? of 4, 3, and 2?

The sum of two or more numbers is the same in whatever order they are added.

WRITTEN EXERCISES

41. 1. Add 3.5, 3.6, 6.2, 7.4, 6.3, 8.4, and 7.8.

12

(3.5 3.6

11

6.2

7.4

9

13

6.3

8.4

15

12

7.8

3.2

40

43.2

We write units of the same order in the same column. Beginning at the bottom of the right-hand column to add, we mentally separate the figures into convenient groups (as indicated), thinking of the total of each and naming results only: "12, 21, 32."

Since this is tenths' column, the footing is not 32, but 32 tenths, or 3.2. This we write below with its right-hand figure under the column just added.

Proceeding in a similar manner, we add the units' column: "15, 28, 40."

Writing 40 below the footing of the previous column and one place to the left, we add the footings and place the decimal point in the sum under the other decimal points.

Test. Add each column in the reverse order. If the results agree, the work is probably correct.

Drill on exercises 2-5 until you can add and test them in 5 minutes or less:

In books of account, dollars and cents are separated by a line, as in the following exercises, instead of by decimal points. Add and test in 6 minutes or less:

11. Add 481 thousand 2 hundred, 7 million 375 thousand 289, 25 million 875, 58 million 5 thousand 96, 32 million 630 thousand 88.

12. Add 37 thousand 250 and 8 hundredths, 64 thousand 208 and 9 tenths, 10 thousand and 70 thousandths, 856 thousand 926 and 25 ten-thousandths, 648 and 126 ten-thousandths, 70 and 2069 ten-thousandths.

13. Add $87.65, $ 19.16, $ 45.07, $92.95, $ 168.20, $ 256.48, $925.18, $374.77, $410.85, $24.32, $528.80, $7.95, $1244.50, $3265.25, $2481.17.

14. Find the sum of six hundred fifty-two thousand five hundred nine, twenty-one thousand eighty-five, seven hundred ninety-one thousand ninety-nine, three hundred eighty-seven thousand six hundred forty, six hundred seventy-five thousand four hundred ninety-six, and seventy thousand twenty.