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15. Writing Numbers in Arabic Figures. The class has already learned to write numbers. Beginning at the left, we write each period by itself, followed by a comma, putting a zero in every vacant place.

Thus, to write thirty million, forty thousand, seven hundred six, we first write the order of millions, 30, followed by a comma; then 40 thousand, placing a zero in the place of hundred-thousands; then, after the comma, 706. The number then stands as follows:

30,040,706.

EXERCISE 2

Write in figures, arranged in periods, the following: 1. Five thousand, eight. 2. Nine thousand, fifty-seven. 3. Seven thousand, two hundred. 4. Eight thousand, one hundred one. 5. Twelve thousand, four hundred forty. 6. Fifteen thousand, six hundred fifty-six. 7. Eighteen thousand, seven hundred forty-nine. 8. Twenty-five thousand, eight hundred eleven. 9. One hundred fifty-two thousand, eighty-eight. 10. Two hundred six thousand, four hundred one. 11. Four hundred forty thousand, one hundred six. 12. Eight hundred seventy-five thousand, twenty. 13. Nine hundred ninety-nine thousand, eighty-four. i4. One million, one thousand, one hundred one. 15. Three million, three hundred fifty-five thousand, six.

16. Twenty-three million, two hundred forty-eight thousand, six hundred forty-four.

17. Eighty-four million, seven hundred six. 18. Forty-two million, one thousand, one hundred. 19. Seventy-eight million, two hundred forty thousand.

20. Sixty-eight million, eight hundred seventy-three thousand.

21. Ninety-one million, two hundred thousand, one hundred fifty-one.

22. One hundred forty million, seven hundred forty-six.

23. Two hundred thirty-three million, one hundred seventeen thousand, eight.

24. Two hundred twenty-two million, two thousand, two hundred two.

25. Three hundred twenty-four million, five hundred sixty-seven thousand, eight hundred ninety.

26. Three hundred ninety-two million, six hundred forty thousand, five hundred seventy-nine.

27. Four hundred forty-four million, two hundred sixtyseven thousand, three hundred eighty-seven.

28. Five hundred twenty-eight million, six hundred twenty-six thousand, eight hundred forty-seven.

29. Nine hundred eighty-seven million, six hundred fiftyfour thousand, three hundred twenty-one.

30. Seven hundred seventy-two million, four hundred seventy-three thousand, five hundred eighty-nine.

31. Eight hundred eighty-eight million, eight hundred eighty-eight thousand, eight hundred eighty-eight.

32. One hundred ninety-eight billion, seven hundred sixtyfive million, four hundred thirty-two thousand, one hundred fifty-seven.

16. Writing United States Money. In writing United States money the dollar sign ($) is written before the number. A period, called a decimal point, is placed between the dollars and the dimes.

For example, 125 dollars is written $125; 10 dollars and 48 cents (that is, 10 dollars, 4 dimes, 8 cents) is written $10.48; 5 dollars and 8 cents is written $5.08.

EXERCISE 3

Read aloud the following:

1. $15. 9. $2.25. 17. $21.00.
2. $24. 10. $3.75. 18. $35.25.
3. $40. 11. $6.42. 19. $42.75.
4. $90. 12. $7.28. 20. $33.03.
5. $2.70. 13. $5.05. 21. $125.50.
6. $1.30. 14. $7.09. 22. $325.75.
7. $4.60. 15. $3.04. 23. $2450.25.
8. $5.20. 16. $9.08. 24. $3575.50.

25. $4825.25. 26. $7275.05. 27. $427.82. 28. $5207.60. 29. $4270.07. 30. $500.05. 31. $5000.05. 32. $9999.99.

33. In 1800 the public debt of our country was $15.63 for each inhabitant; in 1900 it was $14.52..

34. The average amount for each depositor in the savings banks of the United States recently was $429.64.

35. Recently the public debt of the United States was $2,492,231,518.54.

36. The average pay of locomotive engineers on the railroads in our country is about $4.35 a day; conductors average about $3.75 a day.

37. In a certain year the United States produced iron and steel to the value of $804,034,918.75, the value of that produced by the Middle Atlantic States being $478,687,519.80.

17. The Roman Numerals. The Roman notation is used chiefly for numbering chapters and for dates. It employs seven capital letters, as follows:

Letters, I V X L C D M
Values, 1 5

50 100 500 1000

10

The first nine numbers are written thus :

I, II, III, IV or IIII, V, VI, VII, VIII, IX. The tens are written thus :

X, XX, XXX, XL, L, LX, LXX, LXXX, XC. The hundreds are written thus: C, CC, CCC, CD, D, DC, DCC, DCCC, DCCCC or CM.

The numbers from eleven to nineteen are written thus : XI, XII, XIII, XIV, XV, XVI, XVII, XVIII, XIX.

The following are examples of other numbers: XXII = 22 XCVIII - 98 CLXV XXXIV - 34 LXXV = 75 CCLIX 259 XLIX

LXXXI = 81 MDCCXC= 1790 MDCCCCXI or MCMXI 1911

= 165

= 49

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CHAPTER II

ADDITION OF INTEGERS

18. Addition. You have already learned how to add numbers and are now ready to read the definition of addition. The operation of finding a number equal to two or more numbers taken together is called addition.

7 Thus, to add 7 and 8 is to find a number, 15, that is equal to

8 these numbers taken together.

15 ✓

19. Sum. The result obtained by adding is called the sum.

Thus 15 is the sum of 7 and 8.

20. Symbol. The symbol of addition is this form of a cross, t. It is read plus, a word meaning more. 7

The expression 7 + 8 = 15, as you have long ago learned, is +8 read “7 plus 8 equals 15.” Sometimes in school the plus sign 15 is used to indicate addition in a column, as here shown.

21. Like Numbers. Numbers applied to the same unit are called like numbers.

Thus $3 and $5 have the same unit, $1; 3 feet and 2 feet have the same unit, 1 foot; 7 and 15 have the same unit, 1.

22. Addends. The numbers added are called addends. Only like numbers can be added and the sum is like the addends.

That is, we cannot add $2 and 3 yards, or 7 pounds and 4 books. If we add $12 and $13, the sum must be like the addends; that is, it must be $25, not 25 feet. It is true that we can put 4 books with 7 crayons, but we cannot add them so as to get 11 books or 11 crayons; we have to think of them only as things, and say that we have 11 things.

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