Bài 2:
a: \(8m4dm=840cm\)
\(\dfrac{2}{5}m^2=40dm^2\)
\(12m^26dm^2=1206dm^2\)
2h16'=136'
b: \(x-\dfrac{5}{6}=\dfrac{2}{3}\) nên x=2/3+5/6=3/2
\(x\cdot\dfrac{2}{5}=\dfrac{6}{7}\)
nên \(x=\dfrac{6}{7}:\dfrac{2}{5}=\dfrac{30}{14}=\dfrac{15}{7}\)
bài 2)
a) 8m = 800cm
4dm = 40cm
800 + 40 = 840cm
b)
\(\dfrac{2}{5}\times100=40dm^2\)
c)
12m2 = 1200dm2
1200 + 6 = 1206 dm2
d)
2 giờ = 2 x 6 = 120 phút
120 + 16 = 136 phút
bài 3)
\(x-\dfrac{5}{6}=\dfrac{2}{3}\)
\(x=\dfrac{2}{3}+\dfrac{5}{6}\)
\(x=\dfrac{3}{2}\)
\(\dfrac{2}{5}\times x=\dfrac{6}{7}\)
\(x=\dfrac{6}{7}:\dfrac{2}{5}\)
\(x=\dfrac{6}{7}\times\dfrac{5}{2}\)
\(x=\dfrac{15}{7}\)
Bài 2:
8m 4dm = 840cm 12m2 6dm2 = 1206dm2
\(\dfrac{2}{5}m^2=40dm^2\) 2 giờ 16 phút = 136 phút
\(x-\dfrac{5}{6}=\dfrac{2}{3}\) \(\dfrac{2}{5}\times x=\dfrac{6}{7}\)
\(x=\dfrac{2}{3}+\dfrac{5}{6}\) \(x=\dfrac{6}{7}:\dfrac{2}{5}\)
\(x=\dfrac{3}{2}\) \(x=\dfrac{15}{7}\)
