7/5×2/15+1/10×7/15+7/2×4/15
=2/5×7/15+1/10×7/15+1/2×7/15
=(2/5+1/10+1/2)×7/15
=(4/10+1/10+5/10)×7/15
=7/15
五分之七乘以十五分之二加十分之一乘以十五分之七加二分之七乘以十五分之四等?
7/5x2/15+1/10x7/15+7/2x4/15
=2/5x7/15+1/10x7/15+7/15x2
=7/15x(2/5+1/10+2)
=7/15x(4/10+1/10+2)
=7/15x5/2
=7/6
解:7/5×2/15+1/10×7/15+7/2×4/15
=7/15(2/5+1/10+4/2)
=7/15×(4/10+1/10+20/10)
=7/15×25/10
=7/6
7/5×2/15+1/10×7/15+7/2×4/15=14/75+7/150+28/30=(28+7+140)/150=175/150=1+25/150=1又1/6
7/5x2/15+1/10x7/15+7/2x4/15
=2/5x7/15+1/10x7/15+7/15x4/2
=7/15(2/5+1/10+2)
=7/15x(4/10+1/10+2)
=7/15x5/2
=7/6