Evaluate mentally:
Here are two calculations of
Decide if each equation is true or false. Be prepared to explain your reasoning.
Andre and Jada drew base-ten diagrams to represent
If both students represented the sum correctly, what value does each small rectangle represent? What value does each square represent?
Draw or describe a diagram that could represent the sum
Compute each sum. If you get stuck, consider drawing base-ten diagrams to help you.
The applet has tools that create each of the base-ten blocks. This time you need to decide the value of each block before you begin.
Select a Block tool, and then click on the screen to place it.
Click on the Move tool (the arrow) when you are done choosing blocks.
Subtract by deleting with the delete tool (the trash can), not by crossing out.
https://curriculum.illustrativemathematics.org/MS/students/1/5/3/index.html
[Scroll to the tool under "3.2: Calculating Sums"]
To represent
Diego started by drawing 4 rectangles to represent 0.4. He then replaced 1 rectangle with 10 squares and crossed out 3 squares to represent subtraction of 0.03, leaving 3 rectangles and 7 squares in his diagram.
Noah started by drawing 4 rectangles to represent 0.4. He then crossed out 3 of rectangles to represent the subtraction, leaving 1 rectangle in his diagram.
Do you agree that either diagram correctly represents
To represent
Find each difference. If you get stuck, you can use the applet to represent each expression and find its value.
Be prepared to explain your reasoning.
The applet has tools that create each of the base-ten blocks. This time you need to decide the value of each block before you begin.
Select a Block tool, and then click on the screen to place it.
Click on the Move tool (the arrow) when you are done choosing blocks.
Subtract by deleting with the delete tool (the trash can), not by crossing out.
https://curriculum.illustrativemathematics.org/MS/students/1/5/3/index.html
[Scroll to the tool under "3.3: Subtracting Decimals of Different Lengths"]