Subtraction and Addition Concepts

Mrs. Walker teaches how to use a ruler as a number line to add and subtract numbers. The lesson covers representing two-digit sums and differences involving length. Students learn to use the number line for addition and subtraction, and explore measuring length with a number line. The video includes interactive exercises and problem-solving strategies to enhance understanding.

What is the main goal of using a ruler as a number line in this lesson?

• To add and subtract numbers

• To compare different lengths

• To measure the length of objects

• To draw straight lines

How can you represent 20 yards more than 35 yards on a number line?

• Label the endpoint as 20 and count forward by 10s

• Label the endpoint as 35 and count forward by 20

• Label the endpoint as 20 and count backwards

• Label the endpoint as 35 and count forward by 5s

What addition sentence represents 20 more than 35?

• 35 + 25 = 60

• 35 + 15 = 50

• 35 + 20 = 55

• 20 + 35 = 60

When adding 50 to 60 using units of 10, what is the final result?

• 110

• 120

• 90

• 100

How do you show 15 feet less than 55 feet on a number line?

• Count backward by 10s from 55

• Count forward by 10s from 55

• Count backward by 5s from 55

• Count forward by 5s from 55

What subtraction sentence matches 15 less than 55?

• 55 - 5 = 50

• 55 - 10 = 45

• 55 - 15 = 40

• 55 - 20 = 35

How do you represent 25 less than 100 using units of 5?

• Count backward by 10s from 100

• Count forward by 10s from 100

• Count backward by 5s from 100

• Count forward by 5s from 100

What is the subtraction sentence for 25 less than 100?

• 100 - 20 = 80

• 100 - 25 = 75

• 100 - 30 = 70

• 100 - 15 = 85

How can you determine the length of a pencil on a number line that starts at 49?

• Count from 0 to the end of the pencil

• Subtract the starting point from the endpoint

• Add the starting point to the endpoint

• Multiply the starting point by the endpoint

What is the length of the pencil if it starts at 49 and ends at 62?

• 13

• 12

• 11

• 14