This chapter will review regrouping, but move on to 3-Digit Addition & Subtraction. Students will begin by drawing out the addition problems in base 10 with hundreds, tens, and ones. Next, they will break apart numbers into expanded form (hundreds, tens, and ones). Students will practice adding with regrouping ones to tens, and tens to hundreds. They will also practice writing addition sentences with multiple addends, in order to find the missing sum. Following these various methods of addition, students will move on to the concept of subtraction. They will start by drawing pictures in base 10 form to find the difference. Students will also practice circling numbers and underlining questions for word problems, to break them down into easier bits of information to manage. The students will then transition to subtracting numerically, rather than base 10 form. They will practice using mental math to subtract. Then, they will practice regrouping/borrowing with hundreds, tens, and ones. After learning to regroup in subtraction, students will learn to borrow across zeros. Students will complete the chapter by writing and solving subtraction sentences.