Online Math Practice for Grade 3 - Math Worksheets 4 Kids List of Online Worksheets for Grade 3 | Math. Four-Digit Numbers from Words. Four-Digit Numbers in Words. Four-Digit Numbers in Standard Form. Thousands in Expanded Word Form. Four-Digit Numbers in Expanded Form. Four-Digit Numbers in Expanded Product Form. Three-Digit Addition with Regrouping. Three-Digit Addition Word Problems.