Solved Exercises on Money and Time Calculations in Grade 2

Master money and time calculations: counting coins, telling time, solving word problems through these 5 detailed exercises.

Solution: Exercises 1 to 3
1 Counting Coins
Exercise 1
Sarah has 3 quarters, 2 dimes, and 4 pennies. How much money does she have?
Definition:

Counting coins: Adding up the value of each type of coin to find the total amount of money

Coin counting method:
  1. Identify the value of each type of coin
  2. Multiply the number of each coin by its value
  3. Add all the amounts together
Coin Values
Quarter: 25¢
Dime: 10¢
Penny: 1¢
Calculations
3×25¢ = 75¢
2×10¢ = 20¢
4×1¢ = 4¢
Total
75¢ + 20¢ + 4¢ = 99¢
Step 1: Identify coin values

Quarters are worth 25 cents each, dimes are worth 10 cents each, and pennies are worth 1 cent each

Step 2: Calculate value of each type of coin

3 quarters: 3 × 25¢ = 75¢

2 dimes: 2 × 10¢ = 20¢

4 pennies: 4 × 1¢ = 4¢

Step 3: Add all amounts together

75¢ + 20¢ + 4¢ = 99¢

Sarah has 99¢ or $0.99
Final answer:

Sarah has 99 cents or $0.99

Applied rules:

• Coin values: Quarter = 25¢, Dime = 10¢, Nickel = 5¢, Penny = 1¢

• Multiplication: Number of coins × Value per coin

• Addition: Sum all calculated values

2 Telling Time
Exercise 2
What time is shown on the clock if the hour hand is on 3 and the minute hand is on 12?
Definition:

Telling time: Reading the positions of the hour and minute hands on an analog clock

Hour Hand
On 3
Minute Hand
On 12
Time
3:00
Step 1: Read the hour hand

The hour hand is pointing to 3, so it's 3 o'clock

Step 2: Read the minute hand

The minute hand is pointing to 12, which means 0 minutes

Step 3: Combine the readings

It's 3 hours and 0 minutes, which is 3:00

The time is 3:00
Final answer:

The time is 3:00 (three o'clock)

Applied rules:

• Hour hand: Points to the current hour

• Minute hand: Points to the number of minutes past the hour

• Time format: Hour:Minutes

3 Time Duration
Exercise 3
A movie starts at 2:00 PM and ends at 4:00 PM. How long did the movie last?
Definition:

Time duration: The length of time between two moments

Start Time
2:00 PM
End Time
4:00 PM
Duration
4:00 - 2:00 = 2 hours
Step 1: Identify start and end times

Start: 2:00 PM, End: 4:00 PM

Step 2: Subtract the start time from the end time

4:00 PM - 2:00 PM = 2 hours

Step 3: Express the duration

The movie lasted 2 hours

The movie lasted 2 hours
Final answer:

The movie lasted 2 hours

Applied rules:

• Duration formula: End time - Start time

• Same units: Both times must be in the same format (AM/PM)

• Subtraction: Calculate the difference

Money and Time Facts
Duration = End Time - Start Time
Time Duration Formula
Coin Values
Quarter = 25¢
Dime = 10¢
Coin Values
Nickel = 5¢
Penny = 1¢
Time Facts
1 hour = 60 minutes
1 day = 24 hours
Key definitions:

Money: Currency used to buy goods and services

Time: Measurement of duration or intervals

Duration: Length of time between two events

Complete methodology:
  1. Read the problem: Identify what's given and what's needed
  2. Convert units: Make sure all amounts are in the same unit
  3. Choose operation: Addition for counting, subtraction for duration
  4. Calculate: Perform the math operation
  5. Check: Make sure answer makes sense
Tip 1: Remember: $1.00 = 100 cents, so convert dollars to cents before calculating.
Tip 2: Always line up decimal points when adding or subtracting money.
Tip 3: Use analog clocks to practice reading time hands.
Tip 4: Count up from start time to end time to check duration.
Common errors: Forgetting to convert dollars to cents, misreading clock hands, miscalculating time differences.
Practice tips: Count real coins, practice with clocks, solve word problems daily.
Formulas to know by heart:

• Change = Amount Paid - Cost

• Money Left = Starting Amount - Amount Spent

• Duration = End Time - Start Time

• $1.00 = 100¢

• Quarter = 25¢, Dime = 10¢, Nickel = 5¢, Penny = 1¢

Solution: Exercises 4 to 5
4 Money Word Problem
Exercise 4
Tom has $2.50. He spends $1.75 on a book. How much money does he have left?
Definition:

Money remaining: The amount left after spending some money

Starting Amount
$2.50
Amount Spent
$1.75
Remaining
$2.50 - $1.75 = $0.75
Step 1: Identify starting amount

Tom starts with $2.50

Step 2: Identify amount spent

Tom spends $1.75

Step 3: Subtract spent from starting amount

$2.50 - $1.75 = $0.75

Step 4: Express the remaining amount

Tom has $0.75 left

Tom has $0.75 left
Final answer:

Tom has $0.75 left

Applied rules:

• Subtraction: Remaining = Starting amount - Amount spent

• Money calculation: Keep units consistent (dollars)

• Verification: Check that $1.75 + $0.75 = $2.50

5 Time Word Problem
Exercise 5
A soccer game starts at 3:30 PM and lasts for 1 hour and 30 minutes. What time does it end?
Definition:

Time calculation: Finding the end time when given start time and duration

Start Time
3:30 PM
Duration
1 hour 30 minutes
End Time
3:30 + 1:30 = 5:00 PM
Step 1: Identify start time

Game starts at 3:30 PM

Step 2: Identify duration

Game lasts 1 hour and 30 minutes

Step 3: Add duration to start time

3:30 PM + 1 hour = 4:30 PM

4:30 PM + 30 minutes = 5:00 PM

Step 4: State the end time

The game ends at 5:00 PM

Game ends at 5:00 PM
Final answer:

The soccer game ends at 5:00 PM

Applied rules:

• Time addition: End time = Start time + Duration

• Hours and minutes: Add hours first, then minutes

• Carry over: If minutes exceed 60, convert to hours

Detailed Summary: Money and Time Calculations
Complete Learning Summary
Key Concepts & Definitions

Money: Currency used to buy goods and services

Coins: Small pieces of metal money (pennies, nickels, dimes, quarters)

Time: Measurement of duration or intervals

Duration: The length of time between two moments

Change: Money returned when payment exceeds the cost

Core Rules & Principles

• Change Formula: Change = Amount Paid - Cost

• Unit Consistency: Always work in the same units (cents or dollars)

• Duration Formula: Duration = End Time - Start Time

• End Time Formula: End Time = Start Time + Duration

• Coin Values: Quarter = 25¢, Dime = 10¢, Nickel = 5¢, Penny = 1¢

Step-by-Step Method

1. Read: Understand what the problem is asking

2. Identify: Find what information is given

3. Convert: Make sure units are the same (cents, dollars, hours, minutes)

4. Calculate: Use the appropriate formula

5. Check: Verify your answer makes sense

Examples & Applications

Money Example: Item costs $1.25, you pay $2.00 → Change = $2.00 - $1.25 = $0.75

Time Example: Movie starts at 2:00 PM, lasts 2 hours → Ends at 4:00 PM

Complex Example: Event starts at 3:45 PM, lasts 1 hour 30 minutes → Ends at 5:15 PM

Real World: Shopping, cooking, scheduling activities

Tips & Tricks

• Count Up: For change, count up from cost to amount paid

• Use Clock Face: Visualize time on a clock to understand duration

• Estimate First: Get a rough idea before calculating

• Check Your Work: Always verify your answer

• Practice with Real Items: Use actual coins and clocks

Memory Aids

• Money Rhyme: "What you paid minus what it cost, gives you money that you got!"

• Time Rhyme: "Start time plus duration equals end time, that's the way to go!"

• Visual: Think of a number line for money, clock for time

• Memory Trick: Remember 60 minutes in an hour, 100 cents in a dollar

• Key Words: "left over," "how long," "duration" mean subtraction

Tip 1: Practice with real coins to build tactile understanding of values.
Tip 2: Always line up decimal points when adding or subtracting money.
Tip 3: Use analog clocks to practice reading time hands.
Tip 4: Count up from start time to end time to check duration.
Common errors: Confusing coin values, misreading clock hands, miscalculating time differences.
Success strategies: Draw pictures of coins, use physical clocks, practice regularly with real-world scenarios.
Essential Formulas:

• Change = Amount Paid - Cost

• Money Left = Starting Amount - Amount Spent

• Duration = End Time - Start Time

• End Time = Start Time + Duration

• $1.00 = 100¢, Quarter = 25¢, Dime = 10¢, Nickel = 5¢, Penny = 1¢

Questions & Answers

Question: I don't understand how to figure out the time when something starts at 3:45 and lasts for 45 minutes. How do I calculate the end time?

Answer: To find the end time, add the duration to the start time!

  • Start at 3:45
  • Add 45 minutes to 3:45
  • First, add 15 minutes to reach the next hour: 3:45 + 15 minutes = 4:00
  • Then add the remaining 30 minutes: 4:00 + 30 minutes = 4:30

So the event ends at 4:30.

Alternative method: 3:45 + 0:45 = 3 hours and 90 minutes = 4 hours and 30 minutes = 4:30

When minutes add up to 60 or more, convert to hours!

Question: How do I count my coins correctly? I sometimes mix up the values.

Answer: Here's how to count coins correctly:

Remember the values:

  • Penny = 1¢ (smallest coin, copper color)
  • Nickel = 5¢ (medium-sized, silver color)
  • Dime = 10¢ (smallest silver coin)
  • Quarter = 25¢ (largest coin)

Counting method:

  • Sort coins by type
  • Count each type separately: 3 quarters = 3 × 25¢ = 75¢
  • Add all the totals together

Example: 2 quarters (50¢) + 3 dimes (30¢) + 4 pennies (4¢) = 84¢ total

Tip: Always count the highest value coins first (quarters, then dimes, etc.)

Question: How can I check if my money calculation is correct? Sometimes I'm not sure about my answer.

Answer: Here are several ways to check your money calculations:

For making change:

  • Add the change back to the cost: Cost + Change = Amount Paid
  • Example: Item costs $1.25, change is $0.75, check: $1.25 + $0.75 = $2.00

For counting coins:

  • Count again in reverse order
  • Group coins differently and recount
  • Use a calculator to double-check

Other tips for verification:

  • Ensure all terms of the original problem appear in your calculation
  • Use estimation to see if your answer is reasonable
  • Try calculating the problem using a different method

This checking technique is especially useful for catching common errors!