tính
7/15+4/5 35/28-48/64 10/13:3/4
2.Tính (+5) + ( +4) = ? 3.Tính (- 9) + ( - 1) = ? 4.Tính : 28 + (-15) = ? 5.Tính (-15) + 12 = ? 6.Tính (-25) + 25 = ? 7.Tính : 13 - 17 = ? 8.Tính : (-78) - 9 = ? 9.Tính : ( -24) - ( - 16) = ? 10.Tính : 17 - (-3) = 11.Tính nhanh : (-21) - ( 48 + 52 - 21) = ?
2. Tính (+5) + ( +4) = 9
3.Tính (- 9) + ( - 1) = -10
4.Tính : 28 + (-15) = 13
5.Tính (-15) + 12 = - 3
6.Tính (-25) + 25 = 0
7.Tính : 13 - 17 = - 4
8.Tính : (-78) - 9 = - 87
9.Tính : ( -24) - ( - 16) = - 8
10.Tính : 17 - (-3) = 20
11.Tính nhanh : (-21) - ( 48 + 52 - 21) = -100
2, (+5)+(+4)=+9 hoạc 9 cũng được
3, (-9)+(-1)=-10
4, 28+(-15)=13
5, (-15)+12=-3
6, (-25)+25=0
7, 13-17=4
8, (-78)-9=-87
9, (-24)-(-16)=-40
10, 17-(-3)=20
11, (-21+21)-(48-52)=-4
2. (+5) + ( +4) = 9
3. (- 9) + ( - 1) = -10
4. 28 + (-15) = 13
5. (-15) + 12 = - 3
6. (-25) + 25 = 0
7. 13 - 17 = - 4
8. (-78) - 9 = - 87
9.( -24) - ( - 16) = - 8
10. 17 - (-3) = 20
11. (-21) - ( 48 + 52 - 21) = -100
a) 28 + 2x = 35 – (- 13) ; b) - 25 – (x + 5) = 415 + 5(x – 83)
c) 2 (x + 1)2 = - 7 + 15 ; f) (x – 4)2 – 48 = - 12 ;
g) (x + 3)3:3 – 1 = - 10 ; h) (3x + 9)(11 – x) = 0.
a, 28 + 2x = 35 - ( -13 )
=> 2x = 35 + 13 - 28
=>2x = 20
=> x = 10. vậy x = 10
a, \(28+2x=35+13\Leftrightarrow28+2x=48\Leftrightarrow2x=20\Leftrightarrow x=10\)
b, \(-25-x-5=415+5x-415\Leftrightarrow-6x=30\Leftrightarrow x=-5\)
-10/3 + 13/10-1/6+7/10
1-20/6 +39/30-4/24+34/50
15/24-6/26+28/48-30/39+10/24
-5/10+12/28-3/27-7/18+20/35
Tính theo mẫu :
Mẫu : 13/21 + 5/7 = 13/21 + 5 x 3 / 7 x 3 = 13/21 + 15/21 = 28/21
26/81 + 4/27
5/64 + 7/8
\(\dfrac{26}{81}+\dfrac{4}{27}=\dfrac{26+12}{81}=\dfrac{38}{81}\)
\(\dfrac{5}{64}+\dfrac{7}{8}=\dfrac{5+56}{64}=\dfrac{61}{64}\)
\(\dfrac{26}{81}+\dfrac{4}{27}=\dfrac{26}{81}+\dfrac{4\times3}{27\times3}=\dfrac{26}{81}+\dfrac{12}{81}=\dfrac{38}{81}\)
\(\dfrac{5}{64}+\dfrac{7}{8}=\dfrac{5}{64}+\dfrac{7\times8}{8\times8}=\dfrac{5}{64}+\dfrac{56}{64}=\dfrac{61}{64}\)
Tính thuận tiện
a) A=(15 - 6 13/18) : 11 1/27 - 2 1/8 : 1 11/40
b) B=(-3,2) . -15/64 + (0,8 - 2 4/15): 3 2/3
c) C= -7/9 . 4/11 + -7/9. 7/11 + 5 7/9
d) D= 50% .1 1/3 . 10 . 7/35 . 0,75
e) E= (2/5)^2 + 5 1/2 (4,5 - 2) + 23/-4
a: \(=\left(15-6-\dfrac{13}{18}\right):\dfrac{298}{27}-\dfrac{17}{8}:\dfrac{51}{40}\)
\(=\dfrac{149}{18}\cdot\dfrac{27}{298}-\dfrac{5}{3}=\dfrac{3}{2}-\dfrac{5}{3}=\dfrac{9-10}{6}=\dfrac{-1}{6}\)
b: \(=\dfrac{-16}{5}\cdot\dfrac{-15}{64}+\dfrac{-22}{15}:\dfrac{11}{2}\)
\(=\dfrac{3}{4}-\dfrac{4}{15}=\dfrac{29}{60}\)
c: \(=\dfrac{-7}{9}\left(\dfrac{4}{11}+\dfrac{7}{11}\right)+5+\dfrac{7}{9}=\dfrac{-7}{9}+\dfrac{7}{9}+5=5\)
d: \(=\dfrac{1}{2}\cdot\dfrac{4}{3}\cdot10\cdot\dfrac{1}{5}\cdot\dfrac{3}{4}=1\)
e: \(=\dfrac{4}{25}+\dfrac{11}{2}\cdot\dfrac{5}{2}+\dfrac{-23}{4}=\dfrac{204}{25}\)
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50+51+52+53+54+56+57+58+59+60+61+62+63+64+65+66+67+68+69+70=?
a) 3/13 + 7/12 - 10/13 + 5/12 | d) -5/10 + 12/28 - 3/27 - 7/18 + 20/35 |
b) 15/24 - 6/26 + 28/48 - 30/39 + 10/24 | e) 1/56 + 1/72 + 1/90 + 1/110 + 1/132+ 1/156 = |
c) -1/2 + 3/7 - 1/9 - 7/18 + 4/7 = |
Bài 1. Tính giá trị biểu thức
a) A= 1+2-3-4+5+6-7-8+...-79-80+81
b) B= 1-2+3-4+...+99-100
c) -48+48.(-78)+48.(-21)
d) 13.(23+22)-3.(17+28)
e) 34+35+36+37-14-15-16-17
f) -7264+(1543+7264)