within the given time, or drill on Courtis Standard Tests in subtraction until you develop the desired speed and accuracy. Do not copy these problems. Place a sheet of paper beneath the first group and write the results. Fold this set of results under and write those of the next row. To save time make five folds in your paper before you begin to write. How does a clerk in a store count change? Illustration: $.86 out of $1.00. 86 and 4 are 90 and 10 is $1.00. Therefore the change is 14 cents. In the following transactions, count the change as in d 34 V. Subtraction of Fractions What must be added to each of the following fractions 234 02/0 146 4. .6 .75 .12 .03 .004 .163/3 Subtract the following: .099 .061 3 4 14 5. 2-1-1 1 - 1 1 - 1 3 -1 76-11-11-1 3 98.009 56.87 49.516 9. 11.867 40.086 376.2 45.06 VI. Combination of Addition and Subtraction Ten, 15, 20, 25, etc., are multiples of 5; for 5 × 2 = 10, 5 x 3 = 15, etc. What number must be added to each of the given combinations to make the sum the next higher multiple of 5? Illustrative problem: 13 26 39 52 65 78 14 28 42 56 7084 15 30 45 60 75 90 91 104 117 130 143 156 169 98 112 126 140 154 168 182 196 105 120 135 150 165 180 195 210 225 2 3 4 5 6 7 8 9 10 11 12 13 14 15 2. (a) What is the area of a square 2 inches on a side? (b) Since 2 x 2 gives the area of a square, the product 4 is called the square of 2. It is sometimes written thus, 22, and is read "the square of 2" or "2 squared." 3. (a) Look at the numbers in the foregoing table that are in the little squares that form the steps. (b) What kind of number is each one? 4. It is convenient to know some products other than those in the foregoing table. One should know just as readily the squares of the other numbers up to 30, as given in the second table. Knowledge of these squares may be used as a check on other multiplication. For example, if you multiply 23 × 25, you should know that the product should be very near 242 or 576. If by mistake your product is 675, you can see immediately that it is wrong. 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 5. Near what numbers of this table are the following products? |