Generated by SassMeister.com.

SassMeister-input.sass

// ----
// Sass (v3.4.6)
// Compass (v1.0.1)
// ----

.main-menu__item
  color: red
  
$items: (technology: 10, partners: 20, events: 30, about: 40)

@each $item, $pos in $items
  .main-menu__item--#{$item}
    @extend .main-menu__item
    border: 1px solid green
    background-position: 0 -#{$pos}px

SassMeister-output.css

.main-menu__item, .main-menu__item--technology, .main-menu__item--partners, .main-menu__item--events, .main-menu__item--about {
  color: red;
}

.main-menu__item--technology {
  border: 1px solid green;
  background-position: 0 -10px;
}

.main-menu__item--partners {
  border: 1px solid green;
  background-position: 0 -20px;
}

.main-menu__item--events {
  border: 1px solid green;
  background-position: 0 -30px;
}

.main-menu__item--about {
  border: 1px solid green;
  background-position: 0 -40px;
}