Students understand that less than indicates subtraction. So they take away the said amount from the given number. They may count back from the given number to get to the result. In one and two less within 10 worksheet, students get plenty of practice with this concept. 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.