12. 65-20 16. 78-25 13. 86-30 14. 58-16 17. 97-56 18. 41-28 20. 60-18 21. 54-36 22. 85-47 15. 96-42 19. 52-48 23. 91-26 24. What is the difference between 625 and 378? 625 Minuend 378 Subtrahend 247 Difference Subtract first the units, then the tens, then the hundreds. Since 8 units cannot be subtracted from 5 units, how are the 7 units in the difference found? After the units are subtracted, how many tens are there in the minuend? how many in the subtrahend? Since there are more tens in the subtrahend than in the minuend, how are the 4 tens in the difference found? After the tens are subtracted, how many hundreds are there in the minuend? how many in the subtrahend? How are the 2 hundreds in the difference found? What is the difference between 625 and 378? Check: 247 +378 = 625. NOTE. In practice, think: 8 from 15 leaves 7; 7 from 11 leaves 4; 3 from 5 leaves 2. 25. To check the result in subtraction see that the sum of the difference (or the remainder) and the subtrahend is equal to the minuend. Exercise 9 (Accuracy and speed test. Practice until you can subtract the first 32 examples in this exercise in less than 10 minutes. Check all results. In checking do not rewrite the difference and the subtrahend.) Add upwards; subtract across; check by seeing that the sum of the differences is equal to the difference of the sums of the columns. Illustrative Examples 1. There were 380,546 people living in Maryland in 1810 and 1,295,346 in 1910; what was the increase for the hundred years? 1,295,346 the population of Maryland in 1910. 380,546 the population of Maryland in 1810. 914,800 = the increase in the 100 years. 2. The Mississippi River is 3160 miles long and the Arkansas 2170 miles long; what is their difference in length? 3160 mi. the length of the Mississippi River. 2170 mi. = = the length of the Arkansas River. 990 mi. the difference in length. = Exercise 10 1. A man deposited, during a certain week, $ 2275. He drew out at one time $ 280, at another $ 340, and at another $ 1286; how much had he then in the bank? 2. Copy and find the missing remainders: 3. In 1910 the United States produced 695,443,000 bushels of wheat; all the countries of the world produced 3,626,336,000. How much was produced outside of the United States? 4. In 1910 Iowa produced the greatest yield of oats in the United States, 181,440,000 bushels; Illinois produced the next largest quantity, 171,000,000 bushels. What was the difference in yield in the two states? 5. In 1910 Illinois produced more corn than any other state, 414,812,000 bushels; Iowa produced the next greatest quantity, 343,900,000 bushels. What was the difference in yield in these two states? 6. $7500 is to be collected for a poor fund; at the beginning of a certain day $5225 had already been collected. During the day there were made contributions, as follows: $25, $15, $125, and $18. How much more is needed? 7. A farmer sold 4 loads of corn. The wagon and corn were first weighed and afterwards the wagon; find the weight of the corn in each load and fill in the totals: 8. How many years are there between 365 years and 472 years? How many years from 365 years to 472 years (which includes the latter)? How many years from 365 years to 472 years inclusive (which includes both)? Making Change 26. In making change it is customary to add to the amount of the sales enough change to make the sum of the sales and the change equal the money given in payment. Thus, a man bought a basket for 35 cents and gave the merchant a dollar bill; the merchant, using the least number of pieces of money possible, gave the customer a 5-cent piece, a dime, and a half-dollar, and as he did so said, "thirty-five, forty, fifty, one dollar." Exercise 11 Count aloud the change in each of the following, using in each case as few pieces of money as possible: |