15.2mũ3 +4.26-5.12
204- 84:12. 15.2mũ3+4.3mũ2-5.7
5 mũ 6:5 mũ 3+2 mũ3.2mũ 2
Giúp mình 3/4.26 1/5-3/4.4 1/5 Xin đấy
\(\dfrac{3}{4}\cdot26\dfrac{1}{5}-\dfrac{3}{4}\cdot4\dfrac{1}{5}=\dfrac{3}{4}\cdot\left(26\dfrac{1}{5}-4\dfrac{1}{5}\right)=\dfrac{3}{4}\cdot22=\dfrac{33}{2}\)
1) So sánh
\(M=\dfrac{24.5^4+5^4.26
}{5^3.15}\) và \(N=\dfrac{-25}{-2}\)
\(M=\dfrac{5^4\cdot50}{5^3\cdot15}=\dfrac{50}{3}>\dfrac{50}{4}=N\)
27.2^3+4.3^2-5.12^0=
27 . 23 + 4 . 32 - 5 . 120
= 27 . 8 + 4 . 9 - 5 . 1
= 216 + 36 - 5
= 252 - 5
= 247
\(27.2^3+4.3^2-5.12^0\)
\(=27.8+4.9-5.1\)
\(=216+36-5\)
\(=247\)
7/5.8/19+7/5.12/19-7/5.1/18
`@` `\text {Ans}`
`\downarrow`
\(\dfrac{7}{5}\cdot\dfrac{8}{19}+\dfrac{7}{5}\cdot\dfrac{12}{19}-\dfrac{7}{5}\cdot\dfrac{1}{18}\)
`=`\(\dfrac{7}{5}\cdot\left(\dfrac{8}{19}+\dfrac{12}{19}-\dfrac{1}{18}\right)\)
`=`\(\dfrac{7}{5}\cdot\left(\dfrac{20}{19}-\dfrac{1}{18}\right)\)
`=`\(\dfrac{7}{5}\cdot\dfrac{341}{342}=\dfrac{2387}{1710}\)
Thực hiện phép tính sau đây :B=47-[(45.24-5.12)]
\(B=47-\left[1080-60\right]\)
\(B=47-1020\)
\(B=-973\)
TỰ GHI ĐỀ BÀI
B=47-[45.12.2-5.12]
B=47-[45.12-(5.2).12]
B=47-[45.12-10.12]
B=47-[12.(45-10)]
B=47-12.35
B=47-420
B=-373
tinh 1/1.2+3/2.5+7/5.12+13/12.25+21/25.46
\(\frac{1}{1.2}+\frac{3}{2.5}+\frac{7}{5.12}+\frac{13}{12.25}+\frac{21}{25.46}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{12}+\frac{1}{12}-\frac{1}{25}+\frac{1}{25}-\frac{1}{46}\)
\(=1-\frac{1}{46}\)
\(=\frac{45}{46}\)
tinh nhanh
(9.8-12-5.12).(1+2+3+4+5)
(9.8-12-5.12).(1+2+3+4+5)
=(72-12-60).(1+2+3+4+5)
=0.(1+2+3+4+5)
=0
(9.8-12-5.12).(1+2+3+4+5)
=( 70 - 70 ) . 15
= 0 . 15
=0
Tính hợp lí:
a , 45 − 5. 12 + 9 b , − 12 .47 + − 12 .52 + − 12 c , 29. 19 − 13 − 19. 29 − 13
a , − 60 b , − 1200 c , − 130
Sơ đồ con đường |
Lời giải chi tiết |
Áp dụng tính chất phân phối của phép nhân phân phối đối với phép cộng |
a , 45 − 5. 12 + 9 = 45 − 5.9 − 5.12 = 45 − 45 − 60 = − 60 b , − 12.47 + − 12 .52 + − 12 = − 12. 47 + 52 + 1 = − 12.100 = − 1200 c , 29. 19 − 13 − 19. 29 − 13 = 29.19 − 29.13 − 19.29 − 19. − 13 = 29. − 13 − 19. − 13 = − 13. 29 − 19 = − 13.10 = − 130 |