(-2)7/183
A=5+(-7)+9+(-11)+13+(-15)+17+(-19)
B=455+(-311)+789+(-144)
C=183+(-150)+[120+(-183)+150]+(-20)
\(A=\left(-2\right)+\left(-2\right)+\left(-2\right)+\left(-2\right)=-8\)
\(B=\left(455-311-144\right)+789=789\)
\(C=183-150+120-183-150-20=120-20=100\)
A=5+(-7)+9+(-11)+13+(-15)+17+(-19)
B=455+(-311)+789+(-144)
C=183+(-150)+[120+(-183)+150]+(-20)
tinh nhanh nhecac ban
Bài 1. Tính
5/9 + 7/18
3 - 5/6
5/4 x 6/7
2 : 5/8
5/9 + 7/18 = 10/18 + 7/18 = 17/18
3 - 5/6= 18/6 - 5/6 = 13/6
5/4 x 6/7 = 15/14
2 : 5/8 = 2/1 x 8/5 = 16/5
\(\dfrac{5}{9}+\dfrac{7}{18}=\dfrac{10}{18}+\dfrac{7}{18}=\dfrac{17}{18}\)
\(\dfrac{18}{6}-\dfrac{5}{6}=\dfrac{13}{6}\)
\(\dfrac{5}{4}\times\dfrac{6}{7}=\dfrac{30}{28}=\dfrac{15}{14}\)
\(2\times\dfrac{8}{5}=\dfrac{16}{5}\)
Câu 19: Tập hợp P các số tự nhiên có ba chữ số, biết rằng khi chia cho 8 thì dư 7, chia cho 31 thì dư 28, là:
A.P = {183; 431; 687; 919} B. P = {191; 431; 679}
C. P = {183; 679; 431; 927} D. P = {199; 431; 663}
Câu 20: Cho A = 1 + 3 + 32 + 33 + . . . + 3100. Số dư khi chia A cho 13 là:
A.1 B.4 C.12 D.0
Câu 19: Tập hợp P các số tự nhiên có ba chữ số, biết rằng khi chia cho 8 thì dư 7, chia cho 31 thì dư 28, là:
A.P = {183; 431; 687; 919} B. P = {191; 431; 679}
C. P = {183; 679; 431; 927} D. P = {199; 431; 663}
Câu 20: Cho A = 1 + 3 + 32 + 33 + . . . + 3100. Số dư khi chia A cho 13 là:
A.1 B.4 C.12 D.0
Tính hợp lí :
1) ( -81 ). 27 - 34. ( -77 )
2) ( -16 ). 32 - ( -4 )2. 18
3) ( -2 )4. 289 - 16. 189
4) 41. ( -18 ) + 41. ( -81 ) - 41
5) 17. ( -37 ) - 23. 37 - 46. ( -37 )
6) -48 + 48. ( -78 ) + 48. ( -21 )
7) 29. ( -13 ) + 27. ( -29 ) + ( -14 ). ( -29 )
1) $(-81)\cdot27-3^4\cdot(-77)$
$=(-81)\cdot27-81\cdot(-77)$
$=-81\cdot[27+(-77)]$
$=-81\cdot(27-77)$
$=-81\cdot(-50)$
$=81\cdot50$
$=4050$
2) $(-16)\cdot32-(-4)^2\cdot18$
$=(-16)\cdot32-16\cdot18$
$=-16\cdot(32+18)$
$=-16\cdot50$
$=-800$
3) $(-2)^4\cdot289-16\cdot189$
$=16\cdot289+16\cdot(-189)$
$=16\cdot[289+(-189)]$
$=16\cdot(289-189)$
$=16\cdot100$
$=1600$
4) $41\cdot(-18)+41\cdot(-81)-41$
$=1\cdot(-18)+41\cdot(-81)+41\cdot(-1)$
$=41\cdot[(-18)+(-81)+(-1)]$
$=41\cdot(-18-81-1)$
$=41\cdot(-99-1)$
$=41\cdot(-100)$
$=-4100$
5) $17\cdot(-37)-23\cdot37-46\cdot(-37)$
$=17\cdot(-37)+23\cdot(-37)-46\cdot(-37)$
$=-37\cdot(17+23-46)$
$=-37\cdot(40-46)$
$=-37\cdot(-6)$
$=37\cdot6$
$=222$
6) $-48+48\cdot(-78)+48\cdot(-21)$
$=48\cdot(-1)+48\cdot(-78)+48\cdot(-21)$
$=48\cdot[(-1)+(-78)+(-21)]$
$=48\cdot(-1-78-21)$
$=48\cdot(-79-21)$
$=48\cdot(-100)$
$=-4800$
7) $29\cdot(-13)+27\cdot(-29)+(-14)\cdot(-29)$
$=-29\cdot13+27\cdot(-29)+(-14)\cdot(-29)$
$=-29\cdot[13+27+(-14)]$
$=-29\cdot(40-14)$
$=-29\cdot26$
$=-754$
$\text{#}Toru$
Hãy so sánh:
a) A= \(\frac{178}{179}+\frac{179}{180}+\frac{183}{181}\)với 3.
b) A= \(\frac{1+5+5^2+5^3+...+5^{10}+5^{11}}{1+5+5^2+5^3+...+5^9+5^{10}}\)và B=\(\frac{1+7+7^2+7^3+...+7^{10}+7^{11}}{1+7+7^2+7^3+...+7^9+7^{10}}\)
a) A=\(\frac{178}{179}+\frac{179}{180}+\frac{183}{181}\)
ta có :
\(A=\left(1-\frac{1}{179}\right)+\left(1-\frac{1}{180}\right)+\left(1+\frac{2}{181}\right)\)
\(\Rightarrow A=\left(1+1+1\right)-\left(\frac{1}{179}-\frac{1}{180}+\frac{2}{181}\right)\)
\(\Rightarrow A=3-\left(\frac{1}{179}-\frac{1}{180}+\frac{2}{181}\right)< 3\)
Vậy \(A< 3\)
a. Ta có :
\(\frac{178}{179}< 1\left(\frac{1}{179}\right)\)
\(\frac{179}{180}< 1\left(\frac{1}{180}\right)\)
\(\frac{183}{181}>1\left(\frac{3}{181}\right)\left(1\right)\)
Mà \(\frac{3}{181}>\frac{1}{179}+\frac{1}{180}\left(=\frac{359}{32220}< \frac{3}{181}\right)\left(2\right)\)
Từ \(\left(1\right)\&\left(2\right)\Rightarrow\frac{178}{179}+\frac{179}{180}+\frac{183}{181}< 1+1+1\)
Vậy \(A< 3\)
b) \(A=\frac{1+5+5^2+5^3+...+5^{10}+5^{11}}{1+5+5^2+5^3+...+5^9+5^{10}}=5^{11}\)
bn rút gọn là dc
\(B=\frac{1+7+7^2+7^3+...+7^{10}+7^{11}}{1+7+7^2+7^3+...+7^9+7^{10}}=7^{11}\)
\(A=5^{11},B=7^{11}\)
\(\Rightarrow7^{11}>5^{11}\Rightarrow B>A\)
hk tốt #
tinh gia tri cua bieu thuc: 183*2:6*7
b) 564:6+83*2 a) 6450-4000:(610:5-114)
a)\(6450-4000:\left(610:5-114\right)\)
\(=6450-4000:\left(122-114\right)\)
\(=6450-4000:8\)
\(=6450-500\)
\(=5950\)
b)\(564:6+83x2\)
\(=94+166\)
\(=260\)
Tính
a) ( 325 - 47 ) + ( 175 - 53 )
b) ( 756 - 217 ) - ( 183 - 53 )
c) ( -5 ) . 6 . ( -2 ) . 7
d) 24 . 36 - ( -24 ) . 64
e) 24 . 36 - ( -24 ) . 64
a,
\(\left(325-47\right)+\left(175-53\right)\\ =325-47+175-53\\ =325+175-47-53\\ =\left(325+175\right)-\left(47+53\right)\\ =500-100\\ =400\)
b,
\(\left(756-217\right)-\left(183-53\right)\\ =756-217-183+53\\ =756+53-217-183\\ =\left(756+53\right)-\left(217+183\right)\\ =809-400\\ =409\)
c,
\(\left(-5\right)\cdot6\cdot\left(-2\right)\cdot7\\ =\left[\left(-5\right)\cdot\left(-2\right)\right]\cdot\left(6\cdot7\right)\\ =10\cdot42\\ =420\)
d,
\(24\cdot36-\left(-24\right)\cdot64\\ =24\cdot36+24\cdot64\\ =24\cdot\left(36+64\right)\\ =24\cdot100\\ =2400\)
e,
\(24\cdot36-\left(-24\right)\cdot64\\ =24\cdot36+24\cdot64\\ =24\cdot\left(36+64\right)\\ =24\cdot100\\ =2400\)
Bài 1: Tính:
a) (325+175) - (47+53)
= 500-100=400.
b) (756-217) - (183-53)
= 539-150= 389.
c) (-5).(-2).6.7
= 10.42=420
d) 24.36- (-24).64
= 864- (-1536)
= 2400.
Tick mk nha bn!!!!!
So sánh
1/ 179/ 197 và 971/ 917
2/ 183/ 184 và 184/ 183
3/ -3/ 31 và -789/ 3131
1/Vì 179/197<1 ; 971/917>1
=>179/197<971/917
2/Vì 183/184<1 ; 184/183>1
=>183/184<184/183
3/Ta có : -3/31=-3*101/31*101=-303/3131
Vì -303>-789 =>-303/3131>-789/3131 =>-3/31>-789/3131
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