Mental arithmetic level 0

These are not interactive exercises -you need pen and paper to write your answers down.

Doubles

Adding two whole numbers
smaller than 10

Multiplying by 10 and 100

Halves

Adding with a number
sending in '9'

Dividing by 10 and 100

Complements
to 10

Additions

Operations with holes

Complements
to the tenth

Comparing two whole numbers

The date

25 and others

Subracting one whole number
smaller than 10

Which century ?