Slide 1

, , . , , . 7 500 . , . 8 000 . 7 500 , 500 .

, :8000 7500 = 500

, .

. , .

. . ?, , ! , . . .

- ? . =

8 000

- 7 500

= 500 8 000 + 500 - 7 500 = 1 000

, , . (500 + 500)

? . =

8 000

- 7 500

= 500 8 000 - 400 - 7 500 = 7 600 -7 500 = 100

, . (500 - 400)

!

8 - 3= 5 8 3 = 5 8 3 ?

8 3 = 5(8 - 1) 3 = 7 3 = 4, 5 1

(8 - 1) - 3= (5 - 1)8 3 = 511 . ... :10 4 = 6(10 - 5) 4 = 5 4 = 1 5. 6 -1 = 5. :(a x) b = (c x)

8 3 ?

(8 + 1) - 3= (5 +1)8 3 = 5(8 + 1) 3 = 9 3 = 6, 5 + 18 3 = 513 . ... :10 - 4 = 6(10 + 5) 4 = 15 4 = 11 5. 11 - 6 = 5. :(a + x) b = (c + x)

250, ?2. , 400? 250. ( + 250) b = (c + 250) 400. ( - 400) b = (c - 400)4. b = 3000, :(a + 130) - b =(a 45) - b =3. :(a + 130) - b = 3000 + 130 = 3130 b) (a 45) - b = 3000 45 = 29554 8004 7004 6004 5004 4004 3001001001001001001004 7004 6004 5004 4004 3004 200 . . 30 000 5 000 = 25 000 ( 30 000 + 200 ) 5 000 = __________________________25 000 + 200 = 25 200:

7 390 1 796 = 5 594(7 390 + ) 1 796 = 5 600

= ____________________________5 600 - 5 594 = 6

: 5 000, __________________________ ________________________. 1 345, ____________________________ _________________________.

5 0001 345 b 1 478 = 6000

(b 25) 1 478 = ______________________

6 000 25 = 5 975 3 879. , 39?: ______________________________________________________________________

: _______________________________________________________________________

3 879 + 39 = 3 918 39. . . . , , !

1. :

5 000, __________________________ ________________________.

1 345, ____________________________ _________________________.

2. 3 879. , 39?

: _________________________________________________________________

: _________________________________________________________________

3. b 1 478 = 6 000

(b 25) 1 478 = ____________________________________________________________