Part 8

12 - = 4. 12 - = 8. &c.

+ 6 = 9. + 3 = 9. &c.

9. Practice counting objects as far as 100, after which drill frequently in writing and reading the numbers, from the black-board, as far as 100.

10. Use exercises similar to the following:—

(a) 4 4 4 4 9 19 29 39 &c. _

(b) 7 7 7 7 8 68 18 88 &c. _

Let every possible combination be learned so well that the result can be given instantly.

11. For variety, along with the preceding, there may be used exercises similar to the following:—

(a) 2 3 2 1 4 0 1 3 0 4 3 9 8 6 4 0 6 7 6 8 9 5 7 5 _ _

(b) 2 + 8 + 3 + 7 + 5 = . 4 + 9 + 6 + 1 + 3 = .

(c) 21 41 22 32 63 33 64 63 53 _ _

“Carrying” may now be taught.

12. Practice writing and reading numbers of three, and four, figures. The pupils at the same time may be given exercises similar to the following:—

213 321 132 413 234 ___

769 758 897 786 594 ___

Take the last example: the pupil should be taught to think through it rapidly, as follows:—4, 10, 17, 25, 34—write the 4 and carry the 3; 3, 12, 20, 29, 34, 40,—write the 0 and carry the 4; 4, 9, 16, 24, 31, 38; write the whole result.

13. Let the pupils learn to read numbers as high as millions. For a few examples, at first, in subtraction, let the numbers in each order of the minuend be greater than the corresponding ones in the subtrahend; as,

98 45 __

1364 631 ____

9842 3512 &c. ____

Use practical problems.

14. Next, those examples necessitating “borrowing” or “carrying” may be given; as,

137092 72348 ______

6235 4879 ____

The method involving “carrying” is the better one. If equals be added to two numbers, their difference is not changed. In the last example, if 10 is added to 5, to equalize it add 1 to 7, for 10 units of one order equal one unit of the next higher. Adding the 1 to the 7 is called “carrying.”

·· 2 × 1 = 2 :: 2 × 2 = 4 :: : 2 × 3 = 6 :: :: 2 × 4 = 8 &c. &c.

Let the pupils recite the tables orally. Use for drill the following problems:—

987654321 2 _________