Learning math ( addition ) - mid term break activity

This week is mid term break for Richie, since it's only a week, every activity goes as usual except no school.
Monday, Wednesday and Friday is Music and reading lesson
Tuesday and Thursday is Mandarin and Math lesson

Today, mommy introduces him to addition using button kits
he can do sum up from 1 + 1,2,3,4,5,6,7,8,9 without using button kits
But when he does sum up from 2 + 1,2,3,4,5,6,7,8,9 he needs button kits