One Atta Time Flash Cards Distance Learning Create New Sheet Select a Worksheet > Version 1 Version 2 Version 3 Version 4 Version 5 Version 6 Version 7 Version 8 Version 9 Version 10 Grab 'em All Subtracting within 20 (horizontal) 1oa6 Subtract one number from another when both numbers are 20 or less.Use subtraction facts to find the difference quickly and accurately.Understand subtraction as taking away from a starting number.