Examples of checking for reasonableness in first grade math

📚 Quick Study Guide

• 🔢 What is Reasonableness? Reasonableness in math means checking if your answer makes sense in the real world. Does it fit the problem?
• ➕ Addition Check: If you're adding small numbers, the answer should be a little bigger than the biggest number you started with.
• ➖ Subtraction Check: When you subtract, the answer should be smaller than the starting number.
• 🖼️ Use Pictures: Draw pictures to help visualize the problem and see if your answer seems right.
• 🤔 Ask Yourself: Does this answer make sense? Could I have this many things in real life?

🧪 Practice Quiz

1. What is the first step in checking for reasonableness after solving a math problem?
   1. A. Recalculate the entire problem.
   2. B. See if the answer makes sense in the context of the problem.
   3. C. Ask a friend for the answer.
   4. D. Use a calculator.
2. If you added $5 + 3$ and got $15$, which of the following is the best way to check for reasonableness?
   1. A. Say the answer out loud.
   2. B. Check if $15$ is your favorite number.
   3. C. Realize that $15$ is much larger than $5$ and $3$, so it's likely wrong.
   4. D. Ask your teacher.
3. Sarah had 10 cookies and ate 2. She says she has 12 cookies left. What should you do?
   1. A. Agree with her, because she's older.
   2. B. Check if 12 cookies are her favorite.
   3. C. Realize that if she ate cookies, she should have fewer cookies, not more. Her answer isn't reasonable.
   4. D. Offer her another cookie.
4. Which strategy helps most in checking if $7 - 4 = 11$ is reasonable?
   1. A. Recalculating the problem.
   2. B. Drawing pictures of 7 items and taking away 4.
   3. C. Asking someone nearby for the answer.
   4. D. Using a calculator.
5. What does it mean if an answer is 'reasonable' in a math problem?
   1. A. The answer is always correct.
   2. B. The answer is close to what you expected and makes sense.
   3. C. The answer is the highest number possible.
   4. D. The answer is the lowest number possible.
6. If you have 6 apples and give away 3, which answer is NOT reasonable for how many apples you have left?
   1. A. 3 apples
   2. B. 0 apples
   3. C. 9 apples
   4. D. 2 apples
7. You count 8 birds on a tree, and 1 flies away. Which is the most reasonable number of birds left?
   1. A. 10 birds
   2. B. 9 birds
   3. C. 7 birds
   4. D. 1 bird