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Subtraction

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Hello Math Explorer! Get ready for an exciting adventure.

Each topic has fun activities and games to help you learn. Complete all sections to learn well!

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Math Adventure Complete! 🎉

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Math Explorer 🧮

Welcome to the world of computation operations! In this adventure, you'll master essential math skills:

Rounding & Estimation - Learn to simplify calculations

Factors & Multiples - Discover number relationships

HCF & LCM - Find common denominators

Missing Digits - Solve math puzzles

Complete all sections to earn your Math Master badge!

Rounding for Estimation

Rounding numbers makes them simpler to work with. We can estimate sums and differences by rounding numbers to the nearest ten, hundred, or thousand.

How to Round Numbers

Look at the digit to the right of the place you're rounding to:

  • If it's 5 or greater, round up
  • If it's less than 5, round down
Estimating Sums

Round each number to the same place value, then add them together.

Example: 8639 + 8256

Nearest hundred: 8600 + 8300 = 16900

Estimating Differences

Round each number to the same place value, then subtract them.

Example: 6915 - 2535

Nearest hundred: 6900 - 2500 = 4400

How to Play

  • Find the treasure that shows the correct rounded sum/difference
  • Click on the treasure chest with the correct answer
Time
60
Score
0
Lives
3
Round to the nearest hundred: 8639 + 8256
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Space Rounding Adventure

How to Play

  • Destroy asteroids that show the correct rounded sum/difference
  • Click on the asteroid with the correct answer
  • Each correct asteroid gives you 10 points
  • Avoid wrong asteroids or you'll lose lives!
  • Survive as long as you can!
Score
0
Lives
3
Round to the nearest hundred: 6915 - 2535

Rounding Practice

Estimate the value after rounding each number to the nearest hundreds place:
8639 + 8256
1
Round Each Number

8639 → 8600 (since 3 < 5)

8256 → 8300 (since 5 ≥ 5)

2
Perform Calculation

8600 + 8300 = 16900

Estimating Products

Multiplication can be simplified by rounding numbers. This gives us a quick estimate of the product.

Steps for Estimation
  1. Round each number to its highest place value
  2. Multiply the rounded numbers
  3. The result is your estimated product
Example: 461 × 646

Nearest hundred:

461 → 500 (since 6 ≥ 5)

646 → 600 (since 4 < 5)

500 × 600 = 300,000

Important Note

Estimates are not exact answers! They help you check if your actual calculation is reasonable.

Multiplication Estimation

Estimate the product after rounding to the nearest hundred:
461 × 646

Estimating Quotients

Division can be estimated by rounding numbers to make them easier to divide.

Steps for Estimation
  1. Round the dividend and divisor to compatible numbers
  2. Divide the rounded numbers
  3. The result is your estimated quotient
Example: 13,112 ÷ 22

Nearest ten:

13,112 → 13,110

22 → 20

13,110 ÷ 20 = 655.5 ≈ 656

Compatible Numbers Tip

Look for numbers that divide evenly. For 13,112 ÷ 22, you could use:

13,200 ÷ 22 = 600 (since 22 × 600 = 13,200)

Division Estimation

Estimate the quotient after rounding to the nearest ten:
13,112 ÷ 22

Factors & Multiples

Factors and multiples are fundamental concepts in number theory.

Factors

A factor is a number that divides another number exactly without leaving a remainder.

Example: Factors of 12 are 1, 2, 3, 4, 6, 12

Multiples

A multiple is the product of a number and any integer.

Example: Multiples of 5 are 5, 10, 15, 20, 25,...

Relationship

Factors and multiples are related:

  • If A is a factor of B, then B is a multiple of A
  • Every number is both a factor and a multiple of itself
Find factors of: 20
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20 can be represented as:

20 = 1 X 20

X

Click on the arrows to cycle through different factor representations.

How to play:

  1. Pop balloons that are multiples of the target number
  2. You have ❤️❤️❤️ lives and 60 seconds!
Target:
5
Time:
60
Lives:
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Score:
0
Select all factors of 36

HCF & LCM

HCF (Highest Common Factor) and LCM (Lowest Common Multiple) help solve problems involving multiple numbers.

Highest Common Factor (HCF)

The largest number that divides two or more numbers without remainder.

Example: HCF of 12 and 18 is 6

Lowest Common Multiple (LCM)

The smallest number that is a multiple of two or more numbers.

Example: LCM of 4 and 6 is 12

Calculation Methods

Prime Factorization: Break numbers into prime factors

Division Method: Divide numbers by common factors

How to play:

  1. Examine the two numbers displayed
  2. Click on factors that are common to BOTH numbers
  3. The highest common factor will be calculated automatically
24
36

Common factors will appear here

Find the HCF and LCM of 24 and 36
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Prime Factorization

24 = 2 × 2 × 2 × 3

36 = 2 × 2 × 3 × 3

Missing Digits in Subtraction

Find the missing digit in 2-digit subtraction problems.

Problem Solving Approach
  1. Set up the subtraction vertically
  2. Start from the units place
  3. Work your way to the tens place
  4. Use basic subtraction facts to find the missing digit
Example: 56 - B3 = 23

Units place: 6 - 3 = 3 → correct

Tens place: 5 - B = 2 → B = 3

Correct solution: B = 3

Subtraction Missing Digit

A =

Missing Digits (Multiplication/Division)

Solve more complex puzzles by finding missing digits in multiplication and division problems.

Multiplication Strategy
  1. Start from the rightmost digit of the multiplier
  2. Work through each partial product
  3. Consider carrying between columns
  4. Sum partial products carefully
Division Strategy
  1. Start from the leftmost digits
  2. Work through each division step
  3. Consider remainders and their placement
  4. Verify by multiplication (quotient × divisor + remainder)

Multiplication Missing Digits

Find the missing digit A:
3A × 4 = 148

Math Master Results

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