-38 - 24 = ?
Tính: 24/29+7/38+31/38+15/24=...
24/29 + 7/38 + 31/38 + 5/38
Lời giải:
$\frac{24}{19}+\frac{7}{38}+\frac{31}{38}+\frac{5}{38}$
$=\frac{48}{38}+\frac{7}{38}+\frac{31}{38}+\frac{5}{38}$
$=\frac{48+7+31+5}{38}=\frac{91}{38}$
38 + ( - 40 ) + 24
- 28 - ( - 12 ) + ( - 35 ) + 24
1) 38 + ( - 40 ) + 24
= 62 + (-40)
= 62 - 40
= 22
2) - 28 - ( - 12 ) + ( - 35 ) + 24
= -4 - ( - 12) + ( - 35)
= -4 + 12 - 35
= - 39 + 12
= - 27
38 + ( - 40 ) + 24
= ( 38 + 24 ) + ( - 40 )
= 62 + ( - 40 )
= 62 - 40
= 22
- 28 - ( - 12 ) + ( - 35 ) + 24
= - ( 28 - 12 ) + - ( 35 - 24 )
= - 16 + ( - 11 )
= - 27
38 + ( - 40 ) + 24 = 22
- 28 - ( - 12 ) + ( - 35 ) + 24 = -27
A = 5/18*23 + 1/23*24 + 7/24*31 + 2/31*33 + 4/33*37 + 1/38*45 + 7/38*45 + 9/45*54
giải thích r ạ
b, 23.(145 - 17) - 145. (23 - 6)
= 145.23 - 17.23 - 145.23 + 145.6
= (145.23 + 145.6) - (145.23 + 17.23)
= 145.(23 + 6) - 23.(145 + 17)
= 145.29 - 23.162
= 479
c, -38. (25 - 4) + 25. (-4 + 38)
= (-38).25 - 4.(-38) + 25. (-4) + 25.38
= [(-38).25 - 4.(-38)] + [25. (-4) + 25.38]
= (-38).(25 - 4) + 25. [(-4) + 38]
= (-38). 21 + 25.34
= - 798 + 850
= 52
38/24 : (-3) =???
\(\dfrac{38}{24}:\left(-3\right)=-\dfrac{19}{36}\)
Tính M=1/3.8+1/8*13+1/13*18+...+1/33*38;
N=1/3*10+1/10*17+1/17*24+1/24*31+1/31+38
Tính giá trị biểu thức
38*a với a =16 ;24 ;38
vì * là dấu = nên:
38*16=608 38*24=912 38*38=1444
(38 286+24 362):4