3. Written. Add 53, 37, 34, 54, 66, 45, 25, 87. Mentally group the figures which have the sum of 10 or 11, and add rapidly by groups. Thus, in the units' column of this exercise, beginning at the bottom, think, "7, 17, 27, 31, 41," and in the tens' column think, "10, 20, 31, 36." In adding long columns it is advisable to retain the sum of each column so that an error in adding can be easily found. The following groups should be well fixed in mind: Drill on the following exercises until you can add each one up and down (to test) in one minute or less: It is important that the pupils acquire the ability to add numbers written in horizontal lines. In adding numbers written horizontally care should be exercised to combine only units of the same order. Add from left to right and verify the work by adding from right to left. Grouping may be used to advantage in horizontal addition. 13. 145, 267, 384, 426, 937, 851, 912 Add the following by columns and by lines, and check the work by adding the vertical and horizontal totals: 16. Find the cost of the following: sugar, P9.25; rice, P6.75; coffee, P2.85; meat, P1.75; butter, P1.85; potatoes, P 5.95. 29. Define subtraction; minuend; subtrahend; difference. 13. A man had P1450.50 in a bank. He drew out P 375.75 at one time, P425.75 at another time, and P265.35 at another time. How much money had he still in the bank? He drew out the sum of P 375.75, P 425.75, and P265.35, or P Use 1-12, § 5, for practice in horizontal subtraction. 14. Two boys 4200 meters apart are walking toward each other. When one has walked 1485 meters and the other 1575 meters, how far apart are they? 15. A traveler rode 242 kilometers in four days. If he rode 651 Km the first day, 62% Km the second day, and 55% Km the third day, how far did he ride the fourth day? 17. From the table in No. 16 determine how much the area of Mindanao exceeds the areas of Samar, Negros, and Panay, taken together. 18. This table gives the amount of cocoa and chocolate imported into the United States in the years 1901-1905. Find the increase for each year. Also I find the increase of 1905 over 1901, and the total amount imported in 1901 21,580,524 Kg 1902 23,995,727 Kg 1903 29,505,266 Kg 1904 34,051,090 Kg 1905 35,100,839 Kg 2. 4 × 12 6. 3 x 330 10. 80 × 300 14. 10 x P 4.25 17. Define multiplicand; multiplier; product. 18. Define abstract number; concrete number. 9. What will 285 sacks of beans cost at P9.75 a sack? 10. At the rate of 62 kilometers an hour, how far will a train run in 28 hours? 11. A hotel uses 17 kilos of meat a day. At P.95 a kilo, what will be the cost of the meat used in one week? 12. I bought 121 meters of muslin at P.24 a meter, 32 meters of satin at P.90 a meter, and 71 meters of ribbon at P.42 a meter. How much change did I receive from P10 ? 13. If a cubic meter of pressed bricks weighs 2415 kilos, what will be the weight of 27 cubic meters? 14. A farmer sold during one month 75 chickens at P.65 each, 18 dozen eggs at P.35 a dozen, 12 turkeys at P4.50 each, and 15 ducks at P1.10 each. How much did he receive for all? 15. I have a square field 245 meters on a side. At P.121 per meter, how much will it cost to build a fence around the field? 16. A has P44, B has 2 times as much as A, and C has 3 times as much as B. How much have they all together? 17. A dealer bought a barrel of oil containing 140 liters at P.32 a liter. 12 liters were lost by leakage. He sold 75 liters at P.40 a liter and the remainder at P.38 a liter. How much did he gain? |