Idea of Subtract Icon
This is a very simple icon made up on just a single horizontal line. The line is rather thick, however, and it's meant to represent the minus sign that's often seen in mathematics classrooms.
This Subtract icon is made in Material Design style
developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 6,200 icons, all in the same style and quality.