The orienting teaching strategy is often used by teachers to prepare students to learn three-digit addition and subtraction. Orienting establishes a purpose and a background, and provides directions for the lesson at hand. You may read a book that uses a three-digit addition or subtraction example after explaining to students they will be learning a new way to add. Explain how the method makes adding and subtracting large numbers easier. Build on what the students already know about numbers in the ones and tens place. Learning three-digit numbers, which are in the hundreds place, simply builds on the foundation the students are already familiar with.
The guided practice teaching strategy is one in which the teacher guides the entire lesson. Each student has a dry erase marker board, an abacus, and a chalkboard or a worksheet, and the class works together as a whole to work each three-digit addition or subtraction problem. Within this teaching strategy, the teacher provides the problem and assists students as they work the problem out together as a class. Students are expected to calculate the answer, either in pairs or within a group. The teacher will then validate their answers and assist students having difficulties achieving correct answers. Guided practice teaches the class as a group, step-by-step, together.
Working with place value in the hundreds place is sometimes confusing for students. Some students are able to visualize three-digit numbers in their mind, but others need to see the hundreds place physically, directly in front of them. Using a model helps students to physically touch an object, such as an abacus, when learning how to add and subtract three-digit numbers. Students learn how to build on what they have already learned about place value and can use the abacus to solve addition and subtraction problems.
Independent practice is an important teaching strategy. Students must be able to use what they have learned in class and follow through independently. For independent practice, teachers send home worksheet assignments or abacus problems for students to solve. Students must show that they can solve a specific number of problems on their own without the help of their teacher or their peers. The teacher determines the number of problems on the basis of students' age and grade. Students may also be instructed to practice three-digit addition and subtraction at online math websites.