Tính hợp lý
(-15).4 -240:6 + 36: (-2).3
tính hợp lý :240÷(5^3-5^3÷5^2)- 3^6÷3^4 +15 x 11x(13 - 9 )
\(240:\left(5^3-5^3:5^2\right)-3^6:3^4+15\cdot11\cdot\left(13-9\right)\)
\(=240:\left(5^3-5\right)-3^{6-4}+15\cdot11\cdot4\)
\(=240\cdot\left(125-5\right)-3^2+60\cdot11\)
\(=240:120-9+60\cdot\left(10+1\right)\)
\(=2-9+600+60\)
\(=653\)
Tính hợp lý:
-2/9 - 3/4 + 3/5 + 1/15 + 1/57 + 1/3 - 1/36
\(\dfrac{-2}{9}-\dfrac{3}{4}+\dfrac{3}{5}+\dfrac{1}{15}+\dfrac{1}{57}+\dfrac{1}{3}-\dfrac{1}{36}\)
\(=\left(-\dfrac{2}{9}-\dfrac{3}{4}-\dfrac{1}{36}\right)+\left(\dfrac{3}{5}+\dfrac{1}{15}+\dfrac{1}{3}\right)+\dfrac{1}{57}\)
\(=\dfrac{-8-27-1}{36}+\dfrac{9+1+5}{15}+\dfrac{1}{57}\)
\(=-\dfrac{36}{36}+\dfrac{15}{15}+\dfrac{1}{57}\)
\(=\dfrac{1}{57}\)
Tính:
a) (-15).4 - 240 : 6 + 36 : (-2) .3
b) (-2)5+ [(-69) : 3 + 53)].(-2) - 8.
a) (- 15) . 4 – 240 : 6 + 36 : (- 2) . 3 = - 60 – 40 + (- 18) = - 118
b) (- 2)5 + [(- 69) : 3 + 53] . (- 2) – 8
= - 32 + (- 23 + 53) . (- 2) - 8
= - 32 + 30 . (- 2) - 8
= - 32 + (- 60) – 8
= - 100
Tính hợp lý: a) (-37)-14 - 26+37; b) (-15) - 23+ (-85) -77; c) (- 24) + 4 + (- 6) + 26; d) 34 + 35 + 36 + 37-14 - 15 - 16 - 17
bài 1 : tính hợp lý
a -(30+15-21)-(30+15+9) c 27.19+31.27
b 6-5+4-20+21-18 d (-25).64+36.(-25) e 18.36+72.15
a.
= -30-15+21-30-15-9
= (-30 - 30)+(-15-15)+(21-9)
= -60 -30 + 12
= -78
b.
= (6-18)+(-5+4)+(-20+21)
= 12 + (-1) + 1
=12
c.
= 27.(19+31)
=27. 50
= 1350
d.
= (-25).(64+36)
= -25 . 100
= -2500
e. 18.36 + 72.15
= 18.36 + 4.18.15
=18.( 36 + 60)
= 18.96
= 1728
1, Thực hiện phép tính ( tính hợp lý nếu có thể) A, -1/12+4/3 B,(-4/14-3/15)-(1/5-20/35- -1)7 C, 3/5+ -5/20+30/75+ -7/4 D, 5/6. -12/13 + 7/13 E, 2/-9 - 5/-36 - 1/4 F, 2/23 +-5/12+7/18+21/23+ -7/12
c) Ta có: \(\dfrac{3}{5}+\dfrac{-5}{20}+\dfrac{30}{75}+\dfrac{-7}{4}\)
\(=\dfrac{3}{5}+\dfrac{2}{5}+\dfrac{-1}{4}+\dfrac{-7}{4}\)
\(=1-2=-1\)
Giải:
a)-1/12+4/3=-1/12+16/12=15/12=5/4
b)(-4/14-3/15)-(1/5-20/35-(-1)).7
=-17/35-22/35.7
=-17/35-22/5
=-171/35
c)3/5+-5/20+30/75+-7/4
=3/5+-1/4+2/5+-7/4
=(3/5+2/5)+(-1/4+-7/4)
=1+-2
=-1
d)5/6.-12/14+7/13
=-5/7+7/13
=-16/91
e)2/-9-5/-36-1/4
=-1/12-1/4
=-1/3
f)2/23+-5/12+7/18+21/23+-7/12
=(2/23+21/23)+(-5/12+-7/12)+7/18
=1+-1+7/18
=7/18
Tính hợp lý
3^2×9^3×25^2×12^6/3^15×5^4×6^3×4^2
\(\frac{3^2.9^3.25^2.12^6}{3^{15}.5^4.6^3.4^2}=\frac{3^2.3^{2.3}.5^{2.2}.3^6.4^6}{3^{15}.5^4.2^3.3^3.2^{2.2}}=\frac{3^2.3^6.3^6.5^4.2^{2.6}}{3^{15}.3^3.5^4.2^3.2^4}=\frac{3^{14}.2^{12}.5^4}{3^{18}.5^4.2^7}=\frac{2^5}{3^4}=\frac{32}{81}\)
Tính hợp lý :
A = 1/3 + -3/4 + 3/5 + 1/57 + -1/36 + 1/15 + -2/9
B = 1/2 + -1/5 + -5/7 + 1/6 + -3/35 + 1/3 + 1/41
( các bạn giúp mk mau nha ! ! ! ! )
tính bằng cách hợp lý: 5/11-1/2+2/5+6/11+15/25+3/4+5/16