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7. One bag contains 80 pounds of wheat, another contains 60 pounds; how much more does one bag contain than the other?

8. There were 90 peach trees in an orchard; 60. of them were blown down in a storm; how many were left standing?

LESSON IX.

EXERCISE IN MENTAL SUBTRACTION.

1. How much will be left of 100 after subtracting each of the following numbers: 2, 3, 4, 6, 0, 2, 4, 3, 2, 4, 2, 3, 4, 5, 1, 4, 2, 3, 4, 2, 1, 4?

2. How many are 100 less 2, 3, 4, 2, 5, 2, 3, 4, 2, 3, 2, 2, 4, 5, 3, 4, 2, 4, 3, 2, 4, 2, 3, 2, 4, 2, 4, 3? 3. 100 less 3, 5, 2, 2, 1, 3, 2, 5, 2, 4, 2, 3, 4, 2, 3, 2, 4, 3?

4. 100 less 4, 3, 2, 4, 5, 2, 4, 2, 3, 5, 2, 5, 2, 2, 3, 2, 4, 2, 2, 3?

5. 100 less 3, 4, 2, 3, 4, 2, 2, 4, 3, 5, 4, 2, 3, 4, 2, 3, 5, 2, 3 ?

STUDY.-The pupil should repeat the remainder after each consecutive subtraction; thus: (Exercise 1st) 100, 98, 95, 91, 85, &c., at least five times, each time obtaining the same result.

RECITATION.-Exercise 1. Let each member of the class read from the book one or all of these exercises in the same manner as they are studied. Accuracy and rapidity should be required.

Ex. 2. Let the Teacher require the class to make the subtraction

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of each consecutive number mentally, while he dictates it. After each pupil has done this, let him raise his right hand, then call on some one of the class to give the answer. Those who have the same answer, let their hands fall; when the hands are all down, the Teacher may give the correct answer.

LESSON X.

BLACKBOARD EXERCISES.

In which the unit figure of the subtrahend is less than that of the minuend.

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Rule.-II. To the difference of the tens, annex the difference of the unit figures; thus: 9,1; 91: 30, 6; 306, &c.

STUDY AND RECITATION. (See Lesson IX.)

PROBLEMS.

1. There are 109 scholars in a school, and 81 are girls; how many boys are there?

2. A farm is worth $896, and a house is worth $94; how much more is the farm worth than the house?

3. A boy had 348 cents, and he gave away 84 of them; how many had he left ?

4. A has 60 sheep, worth $526; ten of them worth $81, died; what was the value of the rest?

5. A man traveled 890 miles; on his return, he traveled the first day 60 miles; how far had he yet to travel?

6. A drove of cattle is worth $940; a cow worth $50 is taken from it; what is the value of the rest?

7. A drove of cattle is worth $864; an ox worth $72 is taken from it; what is the value of the rest? 8. A horse is worth $209; the wagon is worth $84; how much more is the horse worth than the wagon?

MENTAL EXERCISES.

STUDY AND RECITATION.-See Lesson III, Note.

LESSON XI.

BLACKBOARD EXERCISES.

In which the unit figure of the subtrahend exceeds the unit figure of the minuend.

MODEL OPERATION.

137 186 126 130 142 154 103 170 181 194 39 38 39 31 36 37 34 31 34 33

10, 8; 98

FORM.-9 from 17 leaves 8; 30 from 120 leave 90; 8 and 90 are 98.

7. Rule.-III. Diminish the difference of the tens by one, and annex the unit figure: thus; 10, 8; 98: 15, 8; 148: 9,7; 87: &c.

PROBLEMS.

1. Mary went shopping with 120 cents in her purse, and when she returned she had only 86 cents left; how much did she spend?

2. I sold a lot of wood for $180, and received in payment, cloth worth $79; how much was still due? 3. A man paid $130 to the merchant, and $60 to the blacksmith; how much more did he pay to one than the other?

4. A man traveled 194 miles on a journey; while returning the first day he traveled 55 miles; how many miles had he yet to travel?

5. A cistern which holds 110 gallons, was full in the morning, but at night there were but 31 gallons; how many gallons had leaked out?

6. A farmer bought a carriage for $120, and a harness for $62; how much more did the carriage cost than the harness?

7. Two barrels of potatoes weigh 190 pounds; one of the barrels weighs 87 pounds; what does the other weigh?

8. Two bags of grain weigh 135 pounds, one of the bags weighs 78 pounds; what does the other weigh?

9. A cow and a horse are worth $137; the cow is worth $67; what is the horse worth?

10. A man owed $172; he paid $86; how much does he still owe?

LESSON XII.

BLACKBOARD EXERCISES.

To find the difference between 100 and any number less

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8. Rule.-IV. Diminish the difference of the tens by one, and annex the unit figure; thus: 8,2; 72: 8, 1; 71, &c.

PROBLEMS.

1. There were 100 peach-trees in one orchard; 81 of them were blown down during a storm; how many remained standing?

2. A butcher bought 100 sheep, and killed 37; how many were left alive?

3. A grocer had a tub of butter containing 100 pounds; he sold 48 pounds to Mr. Wilson; how much remained?

4. Charles had 100 cents, and gave 97 cents for knife; how much had he left?

5. A man had $100, and paid $84 for a yoke of oxen; how much had he left?

6. A drover bought 100 sheep, and then sold 36 of them; how many had he left?

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