Subtracting 3-Digit Numbers with Borrowing (Regrouping) — Math Worksheet for 10-Year-Olds

Instructions

Welcome, Agent! Your mission, should you choose to accept it, is to become an expert in subtraction. You will need to use your regrouping (or "borrowing") skills to solve these top-secret problems. Follow the steps for each section carefully.

1. Read the Spy Tip box to review your regrouping strategy.
2. Complete Part 1 and Part 2 by solving the numerical problems.
3. Move on to Part 3 to solve real-world "Field Mission" word problems.
4. In Part 4, analyze the work of a rival agent to find their mistake.
5. If you're ready for a bigger challenge, attempt the optional Challenge Mission.

Your Top-Secret Spy Tip: How to Regroup

When subtracting, if the top digit in a column is smaller than the bottom digit, you need to regroup from the column to the left.

Example: Solve 523 - 148

1. Ones Place: You can't take 8 from 3. Go to the tens place. Borrow 1 ten (which is 10 ones) from the 2. The 2 becomes a 1, and the 3 becomes 13.
   • 13 - 8 = 5
2. Tens Place: You can't take 4 from 1. Go to the hundreds place. Borrow 1 hundred (which is 10 tens) from the 5. The 5 becomes a 4, and the 1 becomes 11.
   • 11 - 4 = 7
3. Hundreds Place: Now you can subtract.
   • 4 - 1 = 3

Answer: 375

Part 1: Basic Training

Solve the following subtraction problems. Show your work!

1. 642

   • 151

2. 825

   • 369

3. 583

   • 274

4. 916

   • 78

Part 2: Double Agent Problems (Regrouping Across Zeros)

These problems are trickier and might require you to regroup more than once. Stay sharp!

1. 705

   • 238

2. 500

   • 184

3. 902

   • 617

4. 400

   • 99

Part 3: Field Missions (Word Problems)

Read each scenario carefully and solve the problem.

1. The agency's cafeteria made 452 cookies for a party. By the end of the night, only 167 cookies were left. How many cookies were eaten?

2. Agent Miller drove 610 miles for his last mission. Agent Sparks drove 385 miles. How many more miles did Agent Miller drive than Agent Sparks?

3. A secret vault contains 800 gold coins. A villain steals 295 of them. How many gold coins are left in the vault?

Part 4: Find the Saboteur's Mistake

A rival agent tried to solve the problem below but made a mistake. Your job is to find the error, explain it, and then solve the problem correctly.

Rival Agent's Work:

725

• 489

  364

1. What was the agent's mistake?

2. Solve the problem correctly in the space below:

   725

   • 489

Optional: Challenge Mission

This is a multi-step problem for expert agents only.

You start your mission with a gadget budget of $950. You buy a grappling hook for $275 and a pair of night-vision goggles for $499. How much money do you have left in your budget?

Answer Key

Part 1: Basic Training

1. 642 - 151 = 491
2. 825 - 369 = 456
3. 583 - 274 = 309
4. 916 - 78 = 838

Part 2: Double Agent Problems

1. 705 - 238 = 467
2. 500 - 184 = 316
3. 902 - 617 = 285
4. 400 - 99 = 301

Part 3: Field Missions (Word Problems)

1. 452 - 167 = 285 cookies were eaten.
2. 610 - 385 = 225 more miles.
3. 800 - 295 = 505 gold coins are left.

Part 4: Find the Saboteur's Mistake

1. Mistake: The agent correctly borrowed from the tens place for the ones (making 2 a 1 and 5 a 15). But in the tens place, they just subtracted 8 from 2 (getting 6, which is incorrect) instead of borrowing from the hundreds place.
2. Correct Answer: 725 - 489 = 236

Challenge Mission

1. First, add the costs: $275 + $499 = $774
2. Then, subtract the total cost from the budget: $950 - $774 = $176 left.