Nada is using ten frames to see if 14 is even or odd.

She knows that even numbers can be grouped into pairs, so she colours 14 squares in two ten frames and tries to see if every square has a partner.

She notices that the first ten frame is full and can always be grouped into pairs. So, to decide if the number is odd or even, she needs to look at the second ten frame, which is the ten frame for the unit digit.

Now it is your turn. Is 17 even or odd? Why?