: 1) ;
2) .
3) ;
4) ;
5)
1.
2.
3.
4.
() 7, 6.
7. , .
62 + 31 = 93 62 + 16 + 15 = 93
62 + 16 = 78 (62 + 16)+15 = 93
78 + 15 = 68 62 + (16+ 15) = 93
5.
() 1, 2, 3, 4, 5*.
2. . :
485 + 237 + 163 = 485 + (237 + 163)= 485 + 400 = 885 . .
3. : 246 + 37+163. : 246 + (37 + 163) = 246 + 200 = 446.
4. , .
 |
1) 2: 2 = 1 () ;
2) 1 + 2 = 3 () ;
3) 1 3 = 3 (2) .
5*. 1) 6 .
 |
2) .
6: 2 = 3 ().
3) (3 ) . (3 3 = 9) .
 |
) 8, 9.
8. 77 50 .
9.
460 + 380 + 40 = 460 + 40 + 380 = (460 + 40) + 380 = = 500 + 380 = 880 . .
7.
8.
44
. .
: 1) ;
2) .
3) ;
4) ;
5)
1.
2.
3.
4.
() 2, 5, 6*.
2. . :
) 51 26 , 26 51. 25, 25 + 26 = 51; 51 - 26 = 25;
) 51 , 51:
51 - = , + = 51 . .
5. , - b. :
) . b, . ?
) b. , ?
) . b , . ?
, .
|
|
|
6*. , . 6 . .
1) 6: 2 = 3 (.) ( );
2) 3 + 6 = 9 (.) .
5.
() 3, 1, 7, 8, 4.
1.
-b = 385 -160 = 225 ()
- b= 400 - 132 = 268 ()
3. . .
4. 710 - = 71; = 639.
7. , .
 |
385 - 250 - 75 = 60 (), 385 - (250 + 75) = 60 ().
8. 5 , 8 . (5 + 3 = 8.) , .
1 = 5 4 = 20 () P2 = 8 4 = 32 ()
S1 = 5 ∙ 5 = 25 (2) S2 = 8 ∙ 8 = 64 (2)
32 - 20 = 12 () 64 - 25 = 39 (2)
) 9, 10.
9.
135 - 25 = 110 ()
135 + 110 = 245 ()
835 - 245 = 590 ()
7.
8.
45
