HANDS-ON
REGROUPING KIT
Subtraction
Designed to meet these objectives:
Math
• Students will use concrete objects to solve subtraction problems.
• Students will understand place value to hundreds.
• Students will solve subtraction problems with regrouping.
Help students understand the concept of subtraction by regrouping with
this hands-on kit! Students manipulate the number tiles to subtract 2- and
3-digit numbers, seeing exactly what happens when numbers need to be
regrouped. Perfect for independent or small-group learning, it’s a great
way to visualize the regrouping process.
What’s Included
• Place value regrouping tray
• 75 number tiles
• 40 self-checking problem cards
• Write & wipe activity card
Using the Kit
Before students use the kit independently, show them the components of
the kit. Point out that the colors of the place value columns on the tray
and activity card match the colors of the tiles. Hold up a problem card
and place it on the tray. Ask a volunteer to read the subtraction problem.
Model solving the problem by using the tiles.
WARNING:
CHOKING HAZARD—Small parts.
Not for children under 3 yrs.
©2010 Lakeshore
(800) 428-4414
www.lakeshorelearning.com
FF298
Ages 6+
Made in China
Begin by counting out and placing the correct place value tiles on the
tray to build the first number of the problem. Write that number on the
activity card.
Write the second number on the activity card, but instead of placing tiles
on the tray, take away that number of tiles. Begin in the ones column. For
example, if the problem is “187 – 159,” there are seven tiles in the ones
column. You will need to take away nine tiles. Since there are not nine
tiles to take, you must take a tile from the tens column, exchange it for 10
ones tiles and place those in the ones column. Now, you have 17 tiles in
the ones column. Take nine away. Count the number of tiles that remain
(eight) and write that number on the activity card.
Repeat the process for the tens and hundreds columns. In the above
example, there are now seven tiles in the tens column. You need to take
away five tiles. That will leave two. Write that number on the activity card.
For this problem you do not need to regroup the hundreds column. There
is 1 hundreds tile in the column and you need to take away one tile. That
leaves zero tiles in that column. The answer is 28.
Show the value for the first number in the problem.
To find the answer, subtract and regroup the tiles!
2
7
1 8 17
159
28
Model the steps again, showing students how to solve a problem that
requires regrouping in the hundreds and tens columns—for example, “325
– 176.” Put the correct tiles on the tray to show 325, then begin taking
tiles away, starting in the ones column. Since there are not enough tiles
in the ones column to take six away, take a tile from the tens column and
place 10 ones tiles in the ones column.
Now there are 15 tiles in the ones column. Take six away, leaving nine
tiles. Move on to the tens column. There is now one tile in the tens
column. Since you need to take away seven tiles, take a tile from the
hundreds column and place 10 tens tiles in the tens column. Now there
are 11 tiles in the tens column. Take seven away, leaving four tiles. Move
on to the hundreds column. Two tiles now remain in the hundreds column.
You need to take one away. That leaves one. The answer is 149.
Point out that the problem cards have the answers on the back, so
students can check their answers. When students understand how to use
the kit, place it in a math center or designated area and allow individuals,
pairs, or small groups to rotate through and use it.
Meeting Individual Needs
ELL
Work with a small group of students to use the kit. Discuss math
vocabulary and show that the ones tiles belong in the ones column, etc.
Once they understand the concept and how to use the kit, allow them to
work in pairs to complete additional problems.
Reteach/Extra Support
Choose the cards that have 2-digit numbers that only need to be regrouped
in the tens column. Solve these problems with the group, creating more
problem cards with this concept if necessary. You may choose to cover
up the hundreds column on the tray. Once students understand how to
regroup the tens, choose cards that regroup hundreds into tens, again
creating extras if necessary. Work up to cards that regroup twice.
Challenge
Provide students with paper and encourage them to create their own
problem cards with subtraction problems that have 4-digit numbers that
need regrouping. Have students add a thousands column to the tray
and make thousands tiles to use. Let them challenge a partner to solve
their problems.
Informal Assessment Ideas
Observe students as they are using the kit, or work with students
individually. Make a copy of the reproducible on the last page of this
guide, and use it to record your observations. Keep this in students’ files
for reference.
3
Subtraction with Regrouping
Observation Sheet
Name Date Uses the place value number tiles to represent
numbers correctly
Uses number tiles to demonstrate understanding
of regrouping
Subtracts numbers correctly after regrouping
Comments o further
N
instruction needed
© Lakeshore
eeds further
N
instruction