There is a number on each card. Calculate with the cards!
Adding cards: Add the numbers on the cards together.
Subtracting cards: Take the second card away from the first.
Adding three cards: Add all three cards together.
Example: 340 and 250 with plus.
340 + 250 = 590, you write that on the question card.
The numbers written in show the answer.
Example
For parents
What does this exercise practice?
Adding and subtracting big numbers safely in your head or semi-written and switching flexibly between the operations.
Common pitfalls
With three cards one is easily forgotten. It helps to tap each card and count out loud before writing down the result.
How to practice at home
Take a pack of cards and write bigger numbers on slips. Draw two cards and quickly say the sum or the difference.
Related: Number Sentences with a Gap, Mental Math with Jottings