Length Word Problems

In second grade, we learn how to measure things. But what happens when we put two things together or cut a piece off? That's where length word problems come in! We use addition and subtraction to solve real-world problems about length.

Look for Clue Words

When you read a word problem, act like a detective and look for clue words:

• Add ($+$): Words like together, total, more, or combined mean you need to add the lengths.
• Subtract ($-$): Words like cut, left, shorter, longer, or difference mean you need to subtract.

Adding Lengths

Sometimes, we need to find the total length of two objects put end-to-end.

Example: A rope is $45$ cm long. Another rope is $38$ cm long. How long are they together?

How to solve: The word "together" tells us to add. $45 + 38 = 83$ The total length is $83$ cm.

Subtracting Lengths

Other times, we start with a long object and cut a piece off, or we want to find out how much is left.

Example: A board is $90$ inches long. You cut off $35$ inches. How long is the board now?

How to solve: The word "cut" means the board is getting shorter, so we subtract. $90 - 35 = 55$ The board is now $55$ inches long.

Comparing Lengths

We also subtract to find out how much longer or shorter one object is compared to another.

Example: A red ribbon is $20$ inches long. A blue ribbon is $12$ inches long. How much longer is the red ribbon?

How to solve: "How much longer" tells us to find the difference between the two lengths by subtracting. $20 - 12 = 8$ The red ribbon is $8$ inches longer.