Grade 5 Worksheets: Multiplying by 10, 100 or 1,000 (missing factors ... Mental math worksheets: Multiplying by 10, 100 or 1,000 (missing factors) Below are six versions of our grade 5 math worksheet on multiplying by 10, 100 or 1,000 with missing factor; each multiplication sentence consists of an integer between 1 and 1,000 multiplied by either 10, 100 or 1,000. Students must calculate the missing factor.