This worksheet gives students an opportunity to apply the concepts of subtraction to find one less within 10. Students recognize less to mean subtraction. As a result, they deduct the specified amount from the given number. They can work backward from the given number to arrive at the answer. Students have lots of practice with this concept in one less within 10 worksheet. In this worksheet, students practice solving problems written in the horizontal format. How numbers are laid out in a problem affects the method a student employs to solve it. Therefore to develop actual fluency and mastery of multiple strategies, students must practice different formats.