1+-10=?
2+...=-10
3+2.345-123=?
4+89-156317=?
5+1212-318332=?
6-1313819+1313383*21
a) 1-2+3-4+5-6+7-8+9-10+11
b)98+87+76+...+21-12-23-34-...-89
a) 1 - 2 + 3 - 4 + 5 - 6 + 7 - 8 + 9 - 10 + 11
= (1 - 2) + (3 - 4) + (5 - 6) + (7 - 8) + (9 - 10) + 11
= -1 + (-1) + (-1) + (-1) + (-1) + 11
= -1 x 5 + 11
= -5 + 11
= 6
b) 98 + 87 + 76 + ... + 21 - 12 - 23 - 34 - ... - 89
= (98 89) + (87 - 78) + ... + (21 - 12) (có 8 nhóm)
= 9 + 9 + ... + 9 (có 8 số 9)
= 9 x 8
= 72
\(1-2+3-4+.....-10+11\)
\(=\left(1-2\right)+\left(3-4\right)+...\left(9-10\right)+11\)
\(=1+\left(-1\right)+\left(-1\right)+\left(-1\right)+\left(-1\right)+11\)
\(=-1\times5+11\)
\(=6\)
a)1-2+3-4+5-6+7-8+9-10+11 b)98+87+76+...+21-12-23-34-...89 =(1-2)+(3-4)+(5-6)+...+(9-10)+11 =(98-89)+(87-67)+...+(21-12)(8 nhóm) =-1+(-1)+....+(-1)+11 =9+9+9+...+9 =-1x5+11 =9x8 =6 =72
A,-5-(21-89+35)-21×(-6) B,4×52-3(24-4) C,47×(45-15)-47×(45+15) D,1-4+7-10+........+-100+103Các bạn nhanh giúp mình nhé ,mình cảm ơn
i) 10^2-60:(5^6:5^4-3.5)
j)2345-1000:[19-2(21-18)^2]
k)205-[1200-(4^2-2.3)^3]:40
l)500-{5[409-(2^3.3-21)^2]+10^3}:15
n)(-23)+13+(-17)+57
o)(-123)+ -13+(-7)
p)-10+45+ (- -455) + -750
h)9.40-37-2.13-52
bài 1:tính số hạng có trong các tổng sau:
1.1-2+3-4+5-6+7-8
2.1-3+5-7+9-11+13-15
3.-1+3-5+7-9+11-13+15
4.2-4+6-8+10-12+14-16+18-20
5.-2+4-6+8-10+12-14+16-18+20
6.2-5+8-11+14-17+20-23+26
7.-1+5-9+13-17+21-25+29-33+37
8.1-5+9-....-81+85-89+93
9.2-4+6-8+....+202-204
10.1-6+11-16+21-....+176-181
câu 10 Tính nhanh
a) 3/5 x 6/7 + 3/5 : 7 + 6/5
b) 2018x ( 1/2 + 1212/2424 )
a, \(\dfrac{3}{5}\) \(\times\) \(\dfrac{6}{7}\) + \(\dfrac{3}{5}\) : 7 + \(\dfrac{6}{5}\)
= \(\dfrac{3}{5}\) \(\times\) \(\dfrac{6}{7}\) + \(\dfrac{3}{5}\) \(\times\) \(\dfrac{1}{7}\) + \(\dfrac{6}{5}\)
= \(\dfrac{3}{5}\) \(\times\) ( \(\dfrac{6}{7}\) + \(\dfrac{1}{7}\)) + \(\dfrac{6}{5}\)
= \(\dfrac{3}{5}\) + \(\dfrac{6}{5}\)
= \(\dfrac{9}{5}\)
b, 2018 \(\times\) ( \(\dfrac{1}{2}\) + \(\dfrac{1212}{2424}\))
= 2018 \(\times\) ( \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\))
= 2018 \(\times\)1
= 2018
a) 3/5 x 6/7 + 3/5 x 1/7 + 6/5
3/5 x ( 6/7 + 1/7 ) + 6/5
3/5 x 7/7 + 6/5
3/5 x 1 + 6/5
3/5 + 6/5
9/5
b) 2018 x ( 1/2 + 1212/ 2424 )
2018 x ( 1/2 + 12/24 )
2018 x ( 1/2 + 1/2 )
2018 x 2/2
2018 x 1
2018
Học tốt
1+2+3+4+5+6+7+89+10
1 + 2 + 3 + 4 + 5 + 6 + 7 + 89 + 10
= (1 + 89) + 2 + (3 + 7) + (4 + 6) + 5 + 10
= 90 + 2 + 10 + 10 + 5 + 10
= 120 + 2 + 5
= 127
1 + 2 + 3 + 4 + 5 + 6 + 7 + 89 + 10
= (1 + 89) + (3 + 7) + (4 + 6) + (2 + 5) + 10
= 90 + 10 + 10 + 7 + 10
= 10. 12 + 7
= 120 + 7
= 127
Tính nhanh :
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10
123 x 45 + 123 x 50 + 123 x 5
Tính nhanh:
1+2+3+4+5+6+7+8+9+10
=(1+9)+(2+8)+(3+7)+(4+6)+10+5
= 10 + 10 + 10 + 10 + 10+5
= 50 + 5
= 55
123*45+123*50+123*5
= 123*(45+50+5)
= 123 * 100
= 12300
K mk nha bn
1+2+3+4+5+6+7+8+9+10
= ( 1+10 ) + ( 2+9) + (3+8) + (4+7) + (5+6)
= 11 + 11 + 11 + 11 + 11
=11 x 5
=55
123 x 45 + 123 x 50 + 123 x 5
= 123 x ( 45 + 50 +5 )
= 123 x 100
=12300
hok tốt .
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = 10 : 2 x 11 = 55
123 x 45 + 123 x 50 + 123 x 5 = 123x ( 45 + 50 + 5) = 123 x 100 = 12300
Tính:
a) -5/7(14/5 - 7/10) : |-2/3| - 3/4(8/9 + 16/3) + 10/3(1/3 + 1/5)
b) 17/-26(1/6 - 5/3) : 17/13 - 20/3(2/5 - 1/4) + 2/3(6/5 - 9/2)
c) -8/9(9/8 - 3/2) + 5/4 : (5/2 - 15/4) - 3/4(10/9 - 8/3) : (-1/3)
d) 21/10 : (12/5 - 9/10) . (-4/7) - 3/2(1/6 - 7/12) + 1/5(3/2 - 1/4)
a) Ta có: \(\dfrac{-5}{7}\left(\dfrac{14}{5}-\dfrac{7}{10}\right):\left|-\dfrac{2}{3}\right|-\dfrac{3}{4}\left(\dfrac{8}{9}+\dfrac{16}{3}\right)+\dfrac{10}{3}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\)
\(=\dfrac{-5}{7}\cdot\dfrac{3}{2}\cdot\dfrac{21}{10}-\dfrac{3}{4}\cdot\dfrac{56}{3}+\dfrac{10}{3}\cdot\dfrac{8}{15}\)
\(=\dfrac{-9}{4}-14+\dfrac{16}{9}\)
\(=\dfrac{-1621}{126}\)
b) Ta có: \(\dfrac{17}{-26}\cdot\left(\dfrac{1}{6}-\dfrac{5}{3}\right):\dfrac{17}{13}-\dfrac{20}{3}\left(\dfrac{2}{5}-\dfrac{1}{4}\right)+\dfrac{2}{3}\left(\dfrac{6}{5}-\dfrac{9}{2}\right)\)
\(=\dfrac{-17}{26}\cdot\dfrac{13}{17}\cdot\dfrac{-3}{2}-\dfrac{20}{3}\cdot\dfrac{3}{20}+\dfrac{2}{3}\cdot\dfrac{-33}{10}\)
\(=\dfrac{3}{4}-1-\dfrac{11}{5}\)
\(=-\dfrac{49}{20}\)
500 + 2345 - 123 + 10 * 10 *20 * 1212 : 20 + 179 - 20 =
500 + 2345 - 123 + 10 * 10 *20 * 1212 : 20 + 179 - 20 = 500 + 2345 - 123 + 121200 + 179 - 20 = 124081