How about the quick calculation of hand and brain in Linping T 1 campus of Guotai Education and Training Center? Is it useful?
It is really useful. Children didn't like math before, so I took a class of quick calculation with hands and brains, but I didn't expect to like mathematical calculation. Moreover, the direct addition and subtraction within 100 is easy to learn, and the computing power has been improved rapidly and significantly. Let children play in school and in middle school.