Bài 33. Tính hợp lí:
1/
173 - (36 + 173) + [(175 - 27)- 175- (-36 +50)]
= 173 - 173 -36 + ( 175 -175 - 27 +36 -50)
= -36 - 27 -50 +36
= -77
2/
- [-171 + (171 +23)]- [172 - (38 + 172)]- 49
= - ( -171 +171 + 23) - ( 172 -38 - 172) - 49
= - 23 -(-38)-49
= -72 +38 = -34
3/
2750 - (2085 + 2750)- [-438 - (29- 438)]
= 2750 - 2085 -2075 -(- 438 - 29 + 438)
= -2085 + 29 = -2056
4/
-482 - (176- 482)- [2750 - (176 + 2750)|
= -482 - 176 +482 - ( 2750 -176 -2750)
= -176 + 176 = 0
5/
-382 - [1925 + (-382)]- [(3210 -697) + (-3210 +597))
=-382 -1925 +382 - (3210 - 697 - 3210 + 597)
= -1925 - (-100) = -1825
6/
[(321 - 797) + (-321 + 697)]-371 - [1900 +(-371)]
=( 321 -797 -321 + 697) - 371 -(1900- 371)
= -100 -371 - 1900 + 371
= -2000
7/
[(-4625 - 164) – (-4625 - 164)]- [(1907 - 2134)- 1907]
= ( -4625 -164 + 4625 + 164) - ( 1907 -2134 -1907)
= -(-2134) = 2134
8/
17450 + (-1865) + (-17450)- (-1865) + (-14) + 147
= 17450 - 17450 - 1865 + 1865 -14 +147
= 133
9/
18950 + (-271) + (-18850)- (-271) + (-48) + 57
= 18950 -18850 -271 +271 - 48 +57
= 100 - 48 +57
= 100 + 9=109
10/
2486 + (-486)- (-697) - (+97) + 58
= 2486 -486 +697 -97 +58
= 2000 + 600 +58
= 2658