Preparing children to be successful in mathematics begins with what they learn before they reach 1st grade. Math knowledge in prekindergarten and kindergarten predicts school achievement in math and in other topics, such as reading. Indeed, early math knowledge is one of the strongest predictors of math grades in high school, high school graduation, and college entry. But children enter kindergarten with a huge range of numerical knowledge and skills. So early educators must be attentive to practices that will aid in closing the gaps in learning. They can attend to this by following the guidance outlined in the National Research Council's report, "Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity," which identified math concepts that young children can and should learn. Especially important are children's competence with quantity and number, as well as geometry and spatial reasoning. The NRC's research summary and recommendations helped guide the Common Core State Standards in mathematics for kindergarten through 2nd grade.