Create or add challenge, so that a task goes a bit beyond what the children can already do. For example, lay out a collection of chips, count them together and then ask a small group of children how many are left after they see you removing some of the chips. The children count the remaining chips to come up with the answer. To add a challenge, you could hide the chips after you remove some, and the children will have to use a strategy other than counting the remaining chips to come up with the answer. To reduce challenge, you could simplify the task by guiding the children to touch each chip once as they count the remaining chips.