6. Add

472 thousand 325, and 678 thousand 400 ten-mil

lionths;

400734, and 4072401 ten-millionths;

25, and thirty-five thousand and 463 hundred-millionths; 3, and three thousand and 496 hundred-millionths; 540, and 437 thousand and fifty hundred-millionths ; 40 millions, and forty-one hundred-millionths.

7. Add

437 thousand 25, and 463 billionths;
567 million, and 4374 billionths;
207 thousand, and 573402 billionths;
200, and three hundred and four billionths;
643 thousand, and thirteen billionths;
50 thousand, and 13 ten-billionths.

8. Add

seven thousand, and 43 ten-billionths;
347 thousand, 247 ten-billionths;
18 hundred ten-billionths;

347 thousand, and 14 ten-billionths;

437 thousand and 5, and one thousand and eight bil

lionths;

3008, and four thousand and four billionths.

9. Add

five thousand 382, and five thousand five ten-billionths; 500 thousand, and five hundred thousand ten-billionths; 5374 hundred-billionths;

3469 hundred-billionths;

5000005 hundred-billionths;

five billion five million five thousand and five hundredbillionths.

10. Add

274 billions 38 thousand, and 14 trillionths ; 274 billions 39 thousand and 15 ten-trillionths; 274 billions 39 thousand and 15 hundred-trillionths; 274 thousand and thirty-nine hundred-trillionths; 274 millions 39 thousand and 15 hundred-trillionths; 274 thousand five hundred and five hundred-billionths. QUESTIONS.-What is the sum of two or more numbers? (30.) What is Addition? (31.) What is the sign of Addition? (32.) What is the sign of equality? (33.) What is the dollar sign? (34.) Illustrate the use of each of the foregoing signs. What is the order of solving a problem? (35.) Analyze an example in Addition, at the blackboard. (36.) How may addition be proved? (36., f.) What is the difference of two or more numbers? (38.) What is Subtraction? (39.) What is the minuend? (40.) What is the subtrahend? (41.) What is the remainder? (42.) of Subtraction? (43.) Analyze an example in blackboard. (44.)

What is the sign Subtraction, at the

11. Add

LESSON VI.

374 thousand, and 83 ten-billionths;
374 thousand, and 83 billionths;

374 thousand, and 83 ten-millionths;

374 thousand, and 83 hundred-billionths;
374 thousand, and 83 hundred-millionths.

12. Add

nine thousand, and nine billionths;

9 thousand, and nine trillionths ;

9 thousand, and nine hundred-trillionths;

9 thousand, and nine hundred-thousandths;

9 thousand, and nine ten-trillionths;

9 thousand, and nine ten-thousandths.

13. Add

9 thousand, and nine ten-billionths;
9 thousand, and nine millionths;
9 thousand, and nine hundred-thousandths;
9 thousand, and nine hundredths ;
9 thousand, and nine ten-thousandths;
9 thousand, and nine thousandths.

14. Add

nine thousand, and nine hundredths;
nine thousand, and nine tenths;

90 thousand, and nine hundred-thousandths;
90 thousand, and nine millionths;

90 thousand, and nine ten-millionths;
90 thousand, and nine hundred-billionths.

15. Add

ninety millions, and nine tenths;

ninety millions, and ninety hundredths;

ninety millions, and nine hundred-thousandths;

ninety millions, and nine thousand ten-thousandths; ninety millions, and ninety thousand hundred-thou sandths;

ninety millions, and nine hundred thousand millionths.

16. Add

90 millions, and nine ten-millionths;

90 millions, and nine hundred-millionths;
90 millions, and ninety hundred-millionths;
90 millions, and ninety billionths;

90 millions, and nine billionths;
90 millions, and nine ten-billionths.

17. Add

37 thousand 40, and 15 thousandths;

42 millions 8, and 13 millionths;
247 thousand, 138 thousandths;

9 thousand 9, and 9 tenths;

9 thousand 9, and 9 hundredths;
9 thousand 900, and 9 thousandths.

18. Add

280 thousand 40, and 30 ten-millionths;
50 millions 37, and 30 hundred-millionths;
3005, and 730 billionths;

490 millions, and 7 tenths;
689743, and 371 millionths;
4703491, and four billionths.

175. SUBTRACTION OF DECIMALS.

From 68.417 take 63.4177.

ANALYSIS. The analysis and proof are the same as in simple subtraction.

EXAMPLES FOR PRACTICE.

25. From ten thousand, take ten thousandths. 26. From ten millions, take ten millionths.

27. From five hundreds, take five hundredths.

28. From eight hundred thousands, take eight hundredthousandths.

29. From five tenths, take five hundredths.

30. From five hundred-thousandths, take five millionths. 31. From eleven, take eleven tenths.

32. From 113, take 113 tenths.
33. From 417, take 1347 millionths.
34. From 8 tenths, take 436 thousandths.

35. From 297 take 4138 thousandths.

36. From 480 thousandths, take 483 ten-thousandths.