Lesson: Subtraction: 4 Digits Trade First
SWBAT subtract whole numbers up to 4 digits using trade-first method.
Materials Needed: DN Worksheet, white board, dry erase markers, graph paper, and Example Chart_5 Digit Addition.
Vocabulary: column-addition method, place value, ones, tens, hundreds, and thousands.
Do Now (2-3 min): Teacher hands the DN Worksheet to students. Students should complete it independently and quietly.
Opening (3- 5 min): Teacher quickly reviews answers to the Do Now and then says, “Today, we are going to review subtraction. We will learning about trade-first subtraction. By the end of this lesson, you will know be able to subtract whole numbers up to 4 digits using trade-first method.”
Direct Instruction (10 min): The teacher will be teaching trade-first subtraction to the students. The steps are as follows.
1. Look at the digits in the 1s place. Ask yourself, “Is the number on the bottom smaller than the number on the top?” If not, trade 1 ten for 10 ones.
2. Look at the digits in the 10s place. Ask yourself, “Is the number on the bottom smaller than the number on the top?” If not, trade 1 hundred for 10 tens.
3. Look at the digits in the 100s place. Ask yourself, “Is the number on the bottom smaller than the number on the top?” If not, trade 1 thousand for 10 hundreds.
4. Subtract each column.
The teacher should stress that all of this is done before the student even begins to subtract. The teacher should then model one problem for the students. See Example Chart_4 Digit Subtraction. The teacher should point out the place value of each column as he/she completes the subtraction for that column. The teacher should model the first example problem and 1 – 2 more problems.
Guided Practice (10 min): The teacher puts up the Guided Practice chart (See Example Chart 4 Digit Subtraction) and the students use graph paper to complete the problems while the teacher circulates to assist.
Independent Practice (10 min): Each student is given a piece of graph paper and asked to copy the problems from the IND Practice Chart (See Example Chart 4 Digit Subtraction). The students should be asked to complete it individually and turn it in.
Closing (2-3 min): Teacher calls the attention of the students back toward the front of the class to ask what they learned about.
|Graph Paper Addition Lesson 1 Classwork||
|Example Chart 4 Digit Subtraction Exemplar||
|DN subtract lesson 3 Starter / Do Now||