<https://ta.khanacademy.org/math/cc-1st-grade-math/cc-1st-place-value#cc-1st-ones-tens>
<http://schema.org/name>
<https://ta.khanacademy.org/math/cc-1st-grade-math/cc-1st-place-value/cc-1st-ones-tens/e/groups-of-tens>