Ruler with stencil (Math)

This is a simple ruler with a stencil designed for easily writing math formulas and expressions. The stencil works only with mechanical pencils or fine-tip markers. The ruler scale goes up to 16 cm and 6 inches. Need a stencil with Latin letters and symbols? Be sure to check out my other model:Ruler with stencil (Latin alphabet)https://makerworld.com/en/models/578271#profileId-498996