MAFS.1.NBT.3.6 Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero differences), using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.
Cognitive Complexity Level: 1-Recall
[divider] [/divider] Students are able to…
- Use strategies and manipulatives to subtract multiples of 10 from a multiple of 10
- Describe patterns with subtraction
- Subtract using mental strategies and create equations
[divider] [/divider] Students are able to…because teachers:
- Provide problems and materials to explore subtraction of multiples of 10 from a multiple of 10
- Make connections to patterns with subtraction
- Pose purposeful questions to elicit student thinking relating to patterns and strategies for subtraction
[divider] [/divider] Questions to ask students:
- Ask: Describe a strategy to subtract some tens from more tens? For example, 50 – 20
- Sample answer that indicates understanding: I can start at the 50 and count back 2 tens. 50, 40, 30. The answer is 30.
- Ask: What happens with the digit in the ones place when you subtract some tens from more tens?
- Sample answer that indicates understanding: In the answer there is a zero in the ones place because both of the values have a 0 in the ones place. 0 – 0 equals 0.
[divider] [/divider] Additional Resources:
Additional in depth content knowledge
Video: Subtracting Multiples of 10
https://www.youtube.com/watch?v=Tc-C_804hdE
[divider] [/divider] Sample Formative Assessment Tasks:
[divider] [/divider] Resources/Tasks to Support Your Child at Home:
- Give your child a set number of objects. Give them a ten number to subtract from the total number of objects. Encourage them to group and subtract by tens until they find the difference.
- Online Video: 10 More or 10 Less (use as a prerequisite for subtracting by ten to help with the understanding of subtracting by multiples of 10)