Adding and Subtracting on Open Number Lines

This video tutorial covers the use of open number lines for addition in second-grade math. It begins with an introduction to the concept, followed by examples using comic strips and guided practice. Students are encouraged to use expanded form and different strategies to simplify addition. The video also includes independent practice exercises and higher-order thinking questions to reinforce learning. Key concepts include breaking numbers into parts and using hops on the number line to find sums.

What is the first step in adding 598 and 123 using an open number line?

• Start at 0 and add 721

• Start at 721 and subtract 123

• Start at 598 and add 123

• Start at 123 and add 598

How can expanded form help in adding numbers on an open number line?

• It eliminates the need for a number line

• It breaks numbers into smaller, manageable parts

• It allows for larger jumps

• It makes subtraction easier

In the comic strip example, what is the sum of 481 and 122?

• 583

• 603

• 503

• 623

What is the sum of 375 and 118 using an open number line?

• 503

• 493

• 513

• 483

How can you simplify the addition of 670 and 232 on an open number line?

• By adding 100, then 132

• By adding 200, then 30, then 2

• By adding 300, then subtracting 68

• By adding 232 directly

What is the sum of 550 and 298 using Lisa's method on an open number line?

• 848

• 852

• 860

• 850

What is the correct vocabulary term to complete the sentence: 'An open number line can be used to ___'?

• add

• divide

• multiply

• subtract