En Español 
Learning to Add and Subtract A WebQuest for 3rd Grade (Math) Designed by ERNESTO BAUTISTA 

Introduction In our everyday life, we encounter math problems constantly for an infinite number of reasons. To tell the time, to estimate how long will it take to get somewhere, to find out if we have enough money to pay for some item or service, or simply to know how many more things do we need for our personal use. It's all a matter of adding or subtracting things, time, or money. We don't realize the importance of these skills until we need them and even more when mistakes on such skills cause problems. Children in 2nd, 3rd, and 4th grade levels study math mainly to acquire the basic skills of addition, subtraction, multiplication, and division. The last two subjects, multiplication and division, are merely grouped processes of the first two, addition and subtraction, substituting them in cases of multiple groups of equal number of elements. Place value also plays an important role in the learning process. Thus if a student encounters trouble finding out differences, values greater than or less than, it is common to see frustration when the child realizes that adding 2 or more digit numbers is not as easy as adding or subtracting 1digit numbers. Children need to have lots of practice before they can really master these skills. Some more and some less, but all children need many hours of practice. The purpose of this lesson is to give that time of practice outside of school for children that need to reinforce their adding and subtracting skills, before jumping into multiplication and division. Many children need much more time to understand multiplication than we have allotted for teaching, because deep in their brains they still don’t understand what exactly is adding or subtracting and how place value affects these processes. Goals The student adds and subtracts to solve meaningful problems involving whole numbers. The student is expected to (a) model addition and subtraction using pictures, words, and numbers; and (b) select addition or subtraction and use the operation to solve problems involving whole numbers through 999. These pages were developed through TeacherTECH, the teacher professional development component of GirlTECH , which is sponsored by the Center for Excellence and Equity in Education (CEEE) with support from the National Science Foundation through EPIC . 