Mastering 2 Digit Subtraction with Open Number Lines

Miss Brogan introduces a strategy for solving two-digit subtraction using an open number line. She explains how to correctly place numbers on the line, emphasizing the importance of understanding whether numbers are increasing or decreasing. The tutorial demonstrates making jumps for tens and hops for ones, breaking down the subtraction of 33 from 94 into manageable steps. The final result of the subtraction is 61.

What is the first step in using an open number line for subtraction?

• Draw the number line

• Place the starting number

• Make jumps for tens

• Subtract the ones

Why do we not place the starting number at the beginning of the number line when subtracting?

• To make room for other numbers

• Because it represents addition

• None of the above

• It's easier to subtract from zero

Why is it important to think before placing the starting number on the number line?

• None of the above

• Both A and B

• To avoid mistakes

• To ensure correct subtraction direction

What does making jumps backwards on the number line signify?

• Division

• Multiplication

• Subtraction

• Addition

How can you subtract 30 using jumps on the number line?

• Both A and B

• Three jumps of 10

• One jump of 30

• Six jumps of 5

What does each jump on the number line represent when subtracting tens?

• None of the above

• An addition of ten

• A subtraction of one

• A subtraction of ten

After subtracting tens, what is the next step?

• Add the tens back

• Start over

• None of the above

• Subtract the ones

How do you represent subtracting ones on the number line?

• None of the above

• By erasing tens

• With big jumps

• With small hops

What is the final answer when subtracting 33 from 94 using the open number line?

• 61

• 57

• 63

• 67

What is the purpose of labeling each jump or hop on the number line?

• To make the number line look neat

• To track the subtraction process

• None of the above

• To confuse the students