My son loved the double digit by single digit multiplication, but could not quite line up the dougle digit by double digit multiplication. He struggled with adding the misaligned columns, and I was ready to give it a rest for a year. However, after one page of this workbook, with the beautifully color coordinated boxes, a lightbulb went off in his head. We did about 3 more pages of this and was ready to head into triple digits, which gave him no problems. I wish there was a similar book for long division.