Base Ten Blocks Regrouping Worksheets: Complete Guide for 2nd Grade

Master place value and regrouping with base ten blocks through visual learning, exercises, and step-by-step solutions.

Base Ten Blocks Concepts
10 Units = 1 Ten | 10 Tens = 1 Hundred
Regrouping Rule
Base Ten Blocks Definition:

Units: Small cubes representing ones (1)

Tens: Rods made of 10 units (10)

Hundreds: Flats made of 10 tens (100)

Block Types:

Unit: Single cube (1) | Ten: Long rod (10) | Hundred: Flat square (100)

Regrouping Method:
  1. Count units: When you have 10 or more units, group them into a ten
  2. Trade units for tens: Exchange 10 units for 1 ten rod
  3. Count tens: When you have 10 or more tens, group them into a hundred
  4. Trade tens for hundreds: Exchange 10 tens for 1 hundred flat
Key Rule: Only keep up to 9 units in the ones place, up to 9 tens in the tens place.
Exchange Rate: 10 of one place value equals 1 of the next higher place value.
Tip 1: Always count units first, then regroup to tens.
Tip 2: Draw circles around groups of 10 when counting.
Tip 3: Write down the number of each type of block after regrouping.
Exercises and Solutions
1 Addition with Regrouping
Exercise 1
Add using base ten blocks: 27 + 15
Problem Setup:

27 = 2 tens + 7 units | 15 = 1 ten + 5 units

27:

+

15:

↓
Step 1: Combine units and tens separately

Units: 7 + 5 = 12 units | Tens: 2 + 1 = 3 tens

Step 2: Regroup 10 units into 1 ten

12 units = 1 ten + 2 units

Step 3: Add the new ten to existing tens

Total tens: 3 + 1 = 4 tens | Remaining units: 2

27 + 15 = 42 (4 tens and 2 units)
Final answer:

27 + 15 = 42

Applied rules:

• Regrouping: 10 units = 1 ten

• Addition: Combine like place values

• Place value: Tens and units stay separate until regrouping

2 Subtraction with Regrouping
Exercise 2
Subtract using base ten blocks: 42 - 17
Problem Setup:

42 = 4 tens + 2 units | Need to subtract 17 = 1 ten + 7 units

42:

Step 1: Check if enough units to subtract

We have 2 units but need to subtract 7 units → Not enough!

Step 2: Break apart one ten to get more units

Take 1 ten (10 units) and add to 2 units = 12 units

Now we have 3 tens and 12 units

Step 3: Subtract units and tens

Units: 12 - 7 = 5 units | Tens: 3 - 1 = 2 tens

42 - 17 = 25 (2 tens and 5 units)
Final answer:

42 - 17 = 25

Applied rules:

• Borrowing: 1 ten = 10 units

• Subtraction: Take away from like place values

• Regrouping: Break apart higher place value when needed

3 Regrouping Practice
Exercise 3
Count and regroup these blocks: 15 units and 8 tens
Problem Setup:

Starting with: 15 units + 8 tens

Before Regrouping:

Step 1: Regroup units to tens

15 units = 1 ten + 5 units (since 10 units = 1 ten)

Step 2: Add the new ten to existing tens

8 tens + 1 ten = 9 tens

Step 3: Write final count

9 tens + 5 units = 95

15 units + 8 tens = 95
Final answer:

15 units + 8 tens = 95

Applied rules:

• Regrouping: Convert extra units to tens

• Place value: Organize blocks by place value

• Counting: Keep track of each place value separately

Worksheets and Practice Problems
Practice Makes Perfect!
Worksheet Exercises
Worksheet Problems:

Problem 1: Draw base ten blocks for 56 and 34, then add them together.

Problem 2: Start with 72 blocks (tens and units), subtract 28 using regrouping.

Problem 3: Regroup 23 units into tens and units.

Worksheet Instructions:
  1. Draw blocks: Sketch units, tens, and hundreds as needed
  2. Combine: Put like blocks together
  3. Regroup: Trade 10 units for 1 ten or 10 tens for 1 hundred
  4. Count: Write the final number in standard form
Success Tip: Always check your work by counting total blocks.
Verification: Add your answer back to the subtracted amount to check.
Tip 1: Use different colors for units, tens, and hundreds.
Tip 2: Circle groups of 10 when regrouping.
Tip 3: Write place value names above each column.
Additional Practice:

• Practice with numbers up to 999 using hundreds blocks

• Try word problems involving regrouping

• Compare numbers using base ten blocks

Questions & Answers

Question: I don't understand why I need to regroup when I have 10 or more units. Why can't I just leave them as units?

Answer: Great question! We regroup because our number system is based on tens. When you have 10 units, that's actually 1 group of ten, which belongs in the tens place. Think of it like money: 10 pennies equal 1 dime. It's the same concept with place value!

Here's why regrouping helps:

  • It keeps our numbers organized by place value
  • It makes adding and subtracting easier
  • It helps us read and write numbers correctly

So when you have 10 or more units, you trade them for 1 ten rod, just like trading 10 pennies for 1 dime!

Question: My child is struggling with subtraction regrouping. How can I help them visualize taking apart a ten block?

Answer: Subtraction regrouping can be tricky! Here's a helpful visualization technique:

  • Show your child a ten rod and explain it's worth 10 units
  • Physically break apart the ten rod into 10 individual unit cubes
  • Point out that 1 ten = 10 units, so the value stays the same
  • Now you have more units to subtract from

You can also use real manipulatives or draw the process step by step. The key is helping them see that breaking apart a ten doesn't change the total amount, just rearranges it.

Practice with smaller numbers first, like 12 - 5, where they clearly need to break apart the ten.

Question: What's the best way to introduce base ten blocks to students who have never seen them before?

Answer: Start with concrete exploration! Here's an effective introduction sequence:

  1. Let students explore the blocks freely - touch, count, compare
  2. Introduce the names: units (small cubes), tens (long rods), hundreds (flats)
  3. Show the relationship: build a ten rod with 10 unit cubes
  4. Have students practice counting by tens using the rods
  5. Build numbers together starting with small ones (like 14, 23)

Make it hands-on and visual from the beginning. Connect to real-world examples like grouping items by tens (packs of pencils, boxes of crayons). This builds the conceptual foundation before moving to abstract problems.

Remember: concrete before abstract is crucial for 2nd graders!