Care must be taken, therefore, in writing numbers to be added, that all the units' digits shall fall in one column, all the tens' digits in the next column (to the left), and all the hundreds' digits in the next column, and so on.

39. To add columns of digits with absolute accuracy and great rapidity is a real accomplishment, and the operation of addition should be continued until both these results are secured. The beginner, however, will need some test of the accuracy of his work. One test is to begin at the bottom of the right-hand column in adding, and write on a piece of waste-paper the entire sum of each column; then to begin at the top of the left-hand column and write also the entire sum of each column; finally, to add the sums obtained in the first addition, and the sums obtained in the second addition, and compare the results.

The study of an example will make the process understood.

to be

By comparing the results we find each sum 3,135,006, and so infer that the operation is correct.

Find the sums of: Ex. 20. 1. 427, 342, 856, 728. 2. 483, 1000, 8000, 648, 3750, 9840. 3. 15, 603, 1145, 6342. 4. 41, 725, 60, 425, 7000, 4900, 398. 5. 39, 876, 5742, 3000, 478, 9873. 6. 327, 4960, 5000, 749, 3000, 7849. 7. 4284, 32, 679, 43, 5006, 7897. 8. 325, 6007, 983, 4050, 678, 9874. 9. 856, 9193, 8765, 4287, 6696, 9185, 979. 10. 7964, 5000, 303, 9784, 5673, 9004. 11. 9007, 34, 6876, 400, 9344, 7879. 12. 45,678, 96, 375, 4784, 9673, 11,980. 13. 7865, 3586, 4321, 8576. 14. 900,542 + 308,970 + 555,674 + 498,785. 15. 456,789 +304,590 + 600,792 +480,893 +514,763. 16. 357,963 +478,497 + 323,484 +596,372 +300,409. 17. 706,963 + 78,405 + 907,342 +503,476. 18. A man bought a sleigh for $142, a carriage for $325,

and a pair of horses for $476. What was the cost of

all ?

19. A man collected on Monday, $1290; on Tuesday, $340;

on Wednesday, $1008. How much was collected in

all ? 20. A lady paid $912 for a piano, $342 for furniture, $187

for linen, $46 for silver. What did she pay for all ? 21. A farmer had in one flock of sheep, 407; in another,

96; and in a third, 2584. How many had he in all?

22. A man owns four houses; the first is worth $47,050 ;

the second, $9106; the third, $1492; the fourth,

$512. What is the value of them all ? 23. Five loads of flour weighed as follows: 3500 pounds,

4967 pounds, 3974 pounds, 7982 pounds, 7963

pounds. What was the weight of the whole? 24. A house was bought for $7895; repairs amounted to

$1500; new fences, $97; repairs on stable, $ 463 ;

furniture, $1285. What was the cost of the whole ? 25. The population of six towns is: 1674, 9008, 3769,

4000, 7096, 3784. Find the whole population. 26. A house lot cost $675; for building the house and fur

nishing materials the carpenters were paid $2245, the masons $540, the painters $320. What was ex

pended on house and lot? 27. A merchant bought carpets to the amount of $4670;

curtains, $300; paper-hangings, $1275; matting,

$9765. What was the cost of the whole? 28. Find the sum of three hundred thousand six hundred

fifty, seven thousand eight hundred thirty-two, eleven thousand five hundred sixty-seven, ten thousand fifty

six, four hundred seventy-two. 29. Find the sum of one hundred sixty-seven thousand,

three hundred sixty-seven thousand, nine hundred six thousand, two hundred forty-seven thousand, ten thousand, seven hundred thousand, nine hundred seventy-six thousand, one hundred ninety-five thou

sand, ninety-seven thousand. 30. Find the sum of two hundred seven, three hundred

sixty-two, nine hundred forty-five, two thousand three hundred forty-three, fifteen thousand six hundred twenty-two, forty-five thousand eight.

31. Add 3 thousand 4 hundred 92, one thousand four, 6

thousand 5 hundred seventy, 42 hundred eleven. 32. Add 386 million 591, 546 million 311 thousand 122,

796 thousand 351, 84 hundred 1, 9 thousand, 86 thousand 521, 3 hundred fifty-eight thousand 6 hundred, 8 million 888 thousand eight hundred eighty

eight, 1 hundred million. 33. Find the sum of six million sixty thousand six, seven

million nine hundred fifty thousand ninety-nine, ten million nine thousand eight hundred seven, three

hundred sixty-seven thousand forty-five. 34. Find the sum of 200 million 302 thousand, 200 thou

sand two hundred, 50 million 50 thousand 50, 25 million 860 thousand, 47 million 467 thousand, 202

million 6367. 35. What is the sum of eighteen thousand three hundred

twenty, seventy-four thousand five hundred six, ten hundred seventeen thousand nine hundred twentyone, fifty-three thousand seven hundred eleven, five hundred seventy-six thousand three hundred four,

six hundred fifty thousand forty-four ? 36. A man drew five loads of bricks; in the first load there

were 4068; in the second, 1342; in the third, 3927; in the fourth, 1694; in the fifth, 2009. How many

in all the loads? 37. What is the united population of the following cities :

Utica, 28,804 ; Lowell, 40,928; Lynn, 28,236; Sa

lem, 24,100; Erie, 19,500; Auburn, 17,225 ? 38. A fruit-grower sent to market the produce of six peach

orchards; from the first, 7000 baskets; from the second, 6973; from the third, 1004; from the fourth, 3276; from the fifth, 1594; from the sixth, 3976. How many baskets in all ?

39. Bought wheat for $7962, corn for $12,649, oats for

$8763; sold the wheat at a profit of $780, the corn at a profit of $920, and the oats at a profit of $ 765.

How much was received for the whole ? 40. A man paid $ 7038 for 782 horses, $7776 for 972

horses, $9948 for 829 horses. How many horses did

he buy, and what sum of money did he pay for all ? 41. How many times does a clock strike from half-past 12

o'clock at night to half-past 12 o'clock at noon ? 42. A gentleman is 19 years older than his sister, and she

is 18 years older than her nephew, who is 15 years of age. How old is the gentleman, and how old is

his sister? 43. Several persons contributed to the building of a college;

A gave $7325, B gave $500 more than A, C gave $40 more than A and B together, and D gave as much as A, B, and C together. What did B, C, and D

give, and what was the whole sum contributed ? 44. Add one million nine hundred seventy-five thousand

six hundred eighty-two, three hundred seventy-six, five million nine hundred seven, thirty-six, seven

hundred sixty thousand nine, five thousand nine. 45. What number must be added to 6 that the right-hand

figure in the sum shall be 0? 1? 2? 3? 4? 5 ? 46. A man divided his estate as follows: To his wife,

$10,560; to his two sons, $ 7325 each; to his daughter, $485 more than each son's share. What was

the whole estate ? 47. A merchant has in his store flour worth $656, sugar

worth $480, molasses worth $325. He owes for freight $125, for expressage $56, and for cartage $78. What is the whole value of his goods ? What is the amount of his debts ?