-14.(13-57)+57.(10-145)
= -14.(-44)+57.(-135)
=616+ ( -7695)
= -7079
thuc hien phep tinh :199.(15-17)-199.(-17+5)
Thuc hien phep tinh hop li(neu co the):
1) 69 .113 - 27. 69 + 69 .14 + 31
2) 90 -(22. 25 - 32. 7)
3) 720 - {40.[(120 - 70) :25 + 23]}
4) 2345 - 1000 :[19 - 2(21 - 18)2]
5) (-23) + 13 + (-17) + 57
6) (-123) + |-13| + (-7)
7) - |-33| +(-15)+ 20 - |45 - 40| - 57
thuc hien phep tinh
B=10+12+14+....+96+98
-145(13-57)+57(10-145)
1,tính
23×(145-17)-145×(23-6)
145×(13-57)+57×(10-146)
- 145.(13-57)+57.(10-145)
.giúp mk tính từg bước vs ạk
1. thuc hien phep tinh
a, 2-4+6-8+...+1998-2000
b, 2-4-6+8+10-12-14+16+...+1994-1996-1998+2000
thuc hien phep tinh:-39.(5-99)+99.(10-99)
thuc hien phep tinh:-39.(5-99)+99.(10-99)
thuc hien phep tinh
a,C=35+38+41...92+95
b,10+12+14+...96+98
giup minh voi minh đang gấp lắm !!!!!!
