a) [ 2,9+(-2,9)] + [ (-4,2)+4,2]+ 3,7
= 0+0+3,7
= 3,7
b)2,8.[(-6,5)+(-3,5)
= 2,8 . (-10)
= -28
c) - 6,37 . ( 0,4 . 2,5 )
= -6,37.1
= -6,37
d) ( -0,125 . 8) .( -5,3)
= -1. ( -5,3)
= 5,3
xong rồi đó
\(a\))\(2,9+3,7+\left(-4,2\right)+\left(-2,9\right)+4,2\)
\(=3,7\)
\(b\))\(\left(-6,5\right).2,8+2,8.\left(-3,5\right)\)
\(=2,8.\left(-6,5-3,5\right)\)
\(=2,8.\left(-10\right)\)
\(=-28\)
\(c\))\(\left(-6,37.0,4\right).2,5\)
\(=\left(-6,37\right).\left(0,4.2,5\right)\)
\(=-6,37\)
\(d\))\(\left(-0,125\right).\left(-5,3\right).8\)
\(=\left(-5,3\right).\left(-1\right)\)
\(=5,3\)
a) Ta có: \(2.9+3.7+\left(-4.2\right)+\left(-2.9\right)+4.2\)
\(=\left(2.9-2.9\right)+\left(-4.2+4.2\right)+3.7\)
\(=0+0+3.7\)
\(=3.7\)
b) Ta có: \(\left(-6.5\right)\cdot2.8+2.8\cdot\left(-3.5\right)\)
\(=2.8\cdot\left(-6.5-3.5\right)\)
\(=2.8\cdot\left(-10\right)\)
\(=-28\)
c) Ta có: \(\left(-6.37\cdot0.4\right)\cdot2.5\)
\(=-6.37\cdot0.4\cdot2.5\)
\(=-6.37\cdot\left(0.4\cdot2.5\right)\)
\(=-6.37\cdot1\)
\(=-6.37\)
d) Ta có: \(\left(-0.125\right)\cdot\left(-5.3\right)\cdot8\)
\(=0.125\cdot8\cdot5.3\)
\(=\left(0.125\cdot8\right)\cdot5.3\)
\(=1\cdot5.3=5.3\)