Fluently Subtracting within 1000

Explicit Instruction/Teacher modeling

• Direct the students’ attention to the board.
• Write a few subtraction problems, within 1,000, on the board, such as 887 – 498 or 978 – 683.
• Tell the students that the first thing we want to do is rewrite the problem in place value format, as follows: (800 + 80 + 7) – (400 + 90 + 8).
• Next, tell the students that we will add the numbers on both sides of the equal sign, based on place value, as follows: (800 – 400) + (80 – 90) + (7 – 8).
• With student input, continue to solve the above problem until you find the answer of 389.

Guided Practice

• Tell the students to pick up their supplies and write down and solve the other problem, 978 – 683, using what’s been termed the "Place Value Method for Subtraction" on the board.
• Ask for volunteers to raise their hands and share with the class the steps involved based on the problem just completed.
• Give the students time to solve the problem.
• As the problem is being solved aloud by the class, write down the steps volunteered by the students on the whiteboard.
• When the problem is done, review it with the class for accuracy. Make sure everyone has the problem written down as a reference for completing their assignment during independent work time.

Independent working time

• Send the students back to their seats.
• Pass out the Subtraction Math worksheets.
• Walk around and observe the students as they work on completing the assignment.
• Monitor the students as they work, making sure the problems are done correctly, in that they are justifying their answers by showing their work.
• During this time, the teacher will ask questions of the students to make sure they understand the concept of subtracting within 1,000 using place value.
• The teacher will also answer questions by the students, to help them clarify any misconceptions they may have.