Review Mistakes
Learn
Everyone makes mistakes! The best learners look at their mistakes and figure out what went wrong. This helps you avoid making the same mistake again.
Why Review Mistakes?
- Mistakes show us what we need to learn
- Understanding errors makes us smarter
- Reviewing helps us remember the right way
- Top test-takers always review their work
Common Mistake Types
Mistake Type 1: Miscount
What happens: You count too fast and skip items or count some twice.
How to fix: Touch or point to each item. Cross off items as you count. Count twice to check.
Mistake Type 2: Wrong Operation
What happens: You add when you should subtract, or subtract when you should add.
How to fix: Look for clue words. "How many in all?" = add. "How many left?" = subtract. "How many more?" = subtract.
Mistake Type 3: Didn't Read Carefully
What happens: You miss an important word or number in the problem.
How to fix: Read the problem twice. Underline the question. Circle important numbers.
Mistake Type 4: Ignored the Diagram
What happens: The diagram has helpful information you didn't use.
How to fix: Always look at the diagram first. Ask "What does this picture tell me?"
Mistake Type 5: Answered the Wrong Question
What happens: You solved the problem but answered something different than what was asked.
How to fix: Re-read the question after solving. Does your answer match what was asked?
Examples of Mistakes
Let's look at some problems where students made mistakes. Can you spot the error?
Example 1: The Miscount
Problem: Count the dots.
. . . . .
. . . .
. . . . . .
Student's answer: 14 dots
What went wrong? The student counted 5 + 4 + 5 = 14, but the bottom row has 6 dots, not 5.
Correct answer: 5 + 4 + 6 = 15 dots
Lesson: Count each row carefully. Point to each dot as you count.
Example 2: Wrong Operation
Problem: Mia has 12 stickers. She gives 5 to her friend. How many does she have left?
Student's answer: 17 stickers (added 12 + 5)
What went wrong? The student added instead of subtracting. "How many left?" means something was taken away.
Correct answer: 12 - 5 = 7 stickers
Lesson: Look for clue words. "Gives away" and "how many left" mean subtract.
Example 3: Didn't Read Carefully
Problem: There are 8 red apples and 6 green apples in a basket. How many red apples are there?
Student's answer: 14 apples (added 8 + 6)
What went wrong? The student added all the apples, but the question only asked about red apples.
Correct answer: 8 red apples (it was given in the problem!)
Lesson: Read the question carefully. Sometimes the answer is already in the problem.
Example 4: Ignored the Diagram
Problem: Look at the picture graph. How many students chose pizza?
Favorite Lunch:
Pizza: [X][X][X][X][X][X]
Sandwich: [X][X][X][X]
Salad: [X][X]
Student's answer: 12 students (added all rows)
What went wrong? The student counted all the students instead of just the pizza row.
Correct answer: 6 students chose pizza
Lesson: Find the right row or column in the graph. Only count what the question asks about.
Practice
For each problem, a student made a mistake. Find the error and solve it correctly.
Problem 1
Count the stars:
* * * *
* * * * *
* * *
Student's answer: 11 stars
What mistake did the student make? _____________
Correct answer: _____________
Problem 2
Jack had 15 marbles. He found 4 more. How many does he have now?
Student's answer: 11 marbles
What mistake did the student make? _____________
Correct answer: _____________
Problem 3
The graph shows favorite colors:
Blue: [X][X][X][X][X]
Red: [X][X][X]
Green: [X][X][X][X]
Yellow: [X][X]
How many more students chose blue than red?
Student's answer: 5 students
What mistake did the student make? _____________
Correct answer: _____________
Problem 4
There are 9 birds on a wire. 3 fly away. Then 2 more birds land on the wire. How many birds are on the wire now?
Student's answer: 4 birds
What mistake did the student make? _____________
Correct answer: _____________
Problem 5
Emma has 7 dolls. Her sister has 5 dolls. How many dolls do they have together?
Student's answer: 2 dolls
What mistake did the student make? _____________
Correct answer: _____________
Problem 6
Look at the shapes:
O [] O O
[] [] O
O O [] O
How many squares are there?
Student's answer: 8 shapes
What mistake did the student make? _____________
Correct answer: _____________
Problem 7
A box has 20 crayons. Tom takes out 8 crayons to draw. How many crayons are still in the box?
Student's answer: 28 crayons
What mistake did the student make? _____________
Correct answer: _____________
Problem 8
The picture graph shows books read:
Amy: [book][book][book][book]
Ben: [book][book][book][book][book][book]
Cara: [book][book][book]
Who read the fewest books? How many?
Student's answer: Ben read 6 books
What mistake did the student make? _____________
Correct answer: _____________
Problem 9
There are 14 students in line. 6 students are boys. How many are girls?
Student's answer: 6 girls (said it's the same as boys)
What mistake did the student make? _____________
Correct answer: _____________
Problem 10
Sam has 11 grapes. He eats some. Now he has 4 grapes. How many did he eat?
Student's answer: 4 grapes
What mistake did the student make? _____________
Correct answer: _____________
Check Your Understanding
Answer Key
- Student miscounted. Correct: 4 + 5 + 3 = 12 stars
- Student subtracted instead of adding ("found more" = add). Correct: 15 + 4 = 19 marbles
- Student just counted blue (5) instead of finding the difference. Correct: 5 - 3 = 2 more students
- Student forgot to add the 2 birds that landed. Correct: 9 - 3 + 2 = 8 birds
- Student subtracted instead of adding ("together" = add). Correct: 7 + 5 = 12 dolls
- Student counted all shapes instead of just squares. Correct: 4 squares
- Student added instead of subtracting ("takes out" = subtract). Correct: 20 - 8 = 12 crayons
- Student answered who read most, not fewest. Correct: Cara read 3 books (fewest)
- Student guessed instead of calculating. Correct: 14 - 6 = 8 girls
- Student wrote what was left, not what was eaten. Correct: 11 - 4 = 7 grapes eaten
Self-Reflection
1. Which mistake type do YOU make most often?
2. What will you do to avoid that mistake?
3. Why is it helpful to check your work?
Next Steps
- Keep a "mistake journal" - write down errors you make and how to fix them
- Before turning in work, always check for the 5 common mistakes
- Move on to the Mixed Set for final practice