Standard: 1.NBT.C6 – 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.
Grade level: Grade 1
Subject: Mathematics
Domain: Number & Operations in Base Ten
Teacher Overview
This standard focuses on helping students understand how to subtract multiples of 10 from each other using various strategies. It’s important because it builds a foundation for more complex arithmetic and helps students grasp the concept of place value. Ensure students can count by tens and have a basic understanding of addition and subtraction. They should also be comfortable using concrete models or drawings to represent numbers.
After mastering this standard, students will be able to tackle more complex subtraction problems and apply their understanding of place value to various mathematical situations.
Common Misconception 1
A common misconception is that subtracting always makes numbers smaller. This is incorrect because it overlooks the specific context of subtracting multiples of 10, which affects the tens place but not necessarily the overall size of the number.
Intervention 1
To address this, use base-ten blocks to visually demonstrate how subtracting multiples of 10 changes the tens place while the ones place remains the same.
Common Misconception 2
Another misconception is confusing subtraction with addition, especially when both involve multiples of 10. This can lead to errors in calculation and understanding.
Intervention 2
Provide differentiated practice problems and use visual aids like number lines to clearly show the difference between addition and subtraction.
Prerequisite Knowledge
Students should understand basic addition and subtraction, be familiar with counting by tens, and have experience with using concrete models or drawings to represent numbers.
Subsequent Knowledge
Students will develop the ability to perform more complex subtraction problems, understand the inverse relationship between addition and subtraction, and apply these skills to solve real-world problems involving larger numbers.
Instructional Activities
- Using base-ten blocks to subtract multiples of 10
- Drawing number lines to visualize subtraction
- Playing games that involve subtracting multiples of 10 from scores
