Simple machines, such as the screw, are important to daily life. This title will help readers understand what a screw is, its parts, and how it makes work easier. This title is complete with colorful and informative images, and simple text. Aligned to Common Core Standards and correlated to state standards. Abdo Kids Junior is an imprint of Abdo Kids, a division of ABDO. Translated by native Spanish speakersand immersion school educators.