Linking the visual representation of digits and numbers and being able to double firstly digits and then all numbers to 100 (using the strategy if I know double 3 ones = 6 then double 3 tens = 6 tens or 60) becomes much easier. Empty columns are for you to add your own headings eg plus 1, plus 10, triple or x 3, double double or x 4, odd or even?, 5 less than or whatever you want to practice.
Dots are used to scaffold numbers up to 20.
Laminate and they can be used over and over.
Multiplicative thinking (compared to additive thinking) is a very important step in thinking mathematically as it is required for algebra. Doubling and halving are the first step in thinking multiplicatively.