Maths challenge

Students will develop their number sense as they try reach a total of 20, by taking it in turns to encircle a number from 1 to 9 and adding these figures to the sum of the previous figures. They must try reach 20 themselves but also prevent their opponent from reaching 20. Extend to 40 for older children.

https://www.mathsweek.ie/2019/maths-at-home-activities/#activity36twentywins