Математика, 3 класс

ВИКИПЕДИЯ: https://ru.wikipedia.org/wiki/%D0%9C%D0%B0%D1%82%D0%B5%D0%BC%D0%B0%D1%82%D0%B8%D0%BA%D0%B0#:~:text=%D0%A1%D0%BB%D0%BE%D0%B2%D0%BE%20%C2%AB%D0%BC%D0%B0%D1%82%D0%B5%D0%BC%D0%B0%D1%82%D0%B8%D0%BA%D0%B0%C2%BB%20%D0%BF%D1%80%D0%BE%D0%B8%D0%B7%D0%BE%D1%88%D0%BB%D0%BE%20%D0%BE%D1%82%20%D0%B4%D1%80,%D0%B7%D0%BD%D0%B0%D0%BD%D0%B8%D0%B5%2C%20%D0%BD%D0%B0%D1%83%D0%BA%D0%B0%2C%20%D0%B8%20%D0%B4%D1%80.