Đáp án:
1, 1125–( 374 + 1125) + (-65 +374) = 1125 - 374 - 1125 - 65 + 374
= (1125 - 1125) + (374 - 374) - 65 = 0 + 0 - 65= -65
2, -23 . 63 + 23 . 21 – 58 . 23 = 23 . (-63) + 23 . 21 – 58 . 23
= 23. (-63 + 21 - 58) = 23. 100 = 2300
3) -2003 + (-21+75 + 2003) = -2003 -21+75 + 2003
= (-2003 + 2003) - 21 +75 = 0-21+75 = 54
4) 942 – 2567 + 2563 – 1942 = ( 942 - 1942) - (2567 -2563) = -1000 - 4= -1004
5) 12-12+11+10-9+8-7+5-4+3+2-1 = (12-12)+(10-9)+(8-7)+(5-4)+(3+11)+(2-1) = 0+1+1+1+14+1= 18
6) 210 + [46 + (–210) + (–26)] =(210 –210)+ (46 –26) = 0+20 = 20
7) (-8) –[(-5) + 8] = (-8) +5 -8 = -16 + 5 = -11
8) 25.134 + 25.(-34) = 25. ( 134-34) = 25. 100 = 2500
9) 17 – 25 + 55 – 17= (17- 17) +( 55 - 25) = 0 + 30 = 30
10) 25 - (-75) + 32 - (32+75) = 25 +75 + 32 - 32-75 = 25 + ( 75 - 75) + ( 32 - 32) = 25 + 0 + 0 = 25
Làm tốt nha có j sai thì thông cảm ạ