Calculer et déterminer la forme irréductible de: 2/5+-3/10x4/6

2/5+-3/10x4/6

=2/5+12/60

=2/5+1/5

=3/5

2/5 + -3/10 x 4/6
= 2/5 + -3x4/10x6
=2/5 + -12/60
= 2/5 + - 12x1/12x5
= 2/5 + - 1/5
= 1/5