This is a basic milestones fact sheet designed to help parents & teachers understand children’s expected addition & subtraction skill level.. Download, Print & Play!. – Know number names. – Confidently count to 20.. The more familiar young children are with numbers the faster they learn. Make a habit of regularly referencing numbers by counting things in everyday life, e.g. “There are 2 cookies left, we can have 1 cookie each”. Available for download after checkout. A copy will also be sent via email