Choosing What to Do!
Chapter 8: Addition & Subtraction Stories
The hardest part of a story problem is not the math. It's deciding: Should I add or subtract? Let's learn to understand the story before we calculate!
The Tricky Words!
Riya is reading a story problem. 🌟
"It says 'Ravi has 5 more marbles than Priya.'"
Milo barks excitedly. "'More' means add, right?"
Riya shakes her head. "Not always, Milo! We need to understand the STORY first!"
Before we do ANY math, let's ask: What is happening in the story?
When we put together or join things, we ADD!
💡 Addition clues: "in all", "altogether", "joined", "got more", "both together" — BUT always check the story meaning!
When things go away, are eaten, or leave, we SUBTRACT!
💡 Subtraction clues: "left", "remaining", "went away", "ate", "gave away", "flew off" — BUT always check the story meaning!
When we compare two groups, we find the difference. This is subtraction!
"How many MORE does Ravi have?"
This says "more" but it's really asking: What's the DIFFERENCE?
Difference = SUBTRACTION!
A good mathematician can explain their thinking. Let's practice!
💡 Good explanations use the story: "I subtract because the birds flew AWAY, so there are fewer birds now."
Questions & Answers
Choosing what to do
How do I know whether to add or subtract?
Ask what the story is doing. If things join or come together, add. If things leave, are taken or compared, subtract.
Which words usually mean add?
Altogether, in total, joined, more came, both. But do not trust words alone. Picture the story first.
Which words usually mean subtract?
Left, gave away, took, flew off, how many more. Again, picture what actually happens before you choose.
Why can key words trick me?
Because the word more appears in both. How many more is a comparison, which is subtraction. Reading the whole story keeps you safe.
What should I do first with a word problem?
Read it twice. Say it in your own words. Draw a quick picture. The picture usually shows you the operation.
What if there are two steps?
Do them one at a time and write down the middle answer. Rushing both steps together is where most mistakes come from.
How do I know my answer makes sense?
Look at it against the story. If a child had 20 sweets and gave some away, the answer cannot be bigger than 20.
Why do we learn story problems?
Because real maths never arrives as a neat sum. It arrives as a situation. Story problems teach you to find the maths inside it.