**Fun with Numbers K. KARTHI & C. SASIKUMAR**

**Making numbers concrete... **CBSE, Mathematics, Class 3, Unit 2

**Objectives**

- To recollect the understanding of the concepts of addition, subtraction and visual estimation of 2-digit numbers.
- To introduce the concept of 3-digit numbers and place value.
- To enhance Mathematisation of the child's thinking.

## ENGAGE

**I) Work with pebbles/beads (Addition & Subtraction)**

- Group children into groups of 4-5. (The teacher could form the groups in a manner that there is at least one student who can provide peer support to the others while the teacher is going around supervising the activity)
- Place a bunch of pebbles (or beads, seeds) in front of different groups. Also give them a box of spare pebbles (or beads, seeds) that will be used later in the activity.
- Children could be given a few tasks step by step:

- Count the number of objects.
- Remove 7 objects from the group and find the no. of remaining objects
- Add 12 objects and find the revised number of objects …and so on
- Teacher' s role - The teacher needs to go around in the groups a n d a s k s t u d e n t s h o w t h e y arrived at the answer. If they are counting the remaining objects, the teacher can help them do it by t h e p r o c e s s o f a d d i t i o n / s u b t r a c t i o n u s i n g a p a p e r and pencil
- At the end, a bunch of pebbles/beads could be kept and one volunteer student in every group could be asked to guess the total quantity without counting. Other students in the group could verify.

*[Since the students have learnt the numbers 1-99 in their previous standard, this will help the students to test their prior knowledge and participate in theclassroomactivities]*

**II) Stick game (or) Beads in a string:**

Ensure that students are familiar with stick (beads) and rubber band (string) to represent 2-digit numbers. Eg.

- 43 is made with 4 bundles of tens and 3 singles (refer image below)
- Similarly 74 is made with 7 bundles of tens and 4 singles
- 51 is made with 5 bundles of tens and 1 single.
- 99 is made with 9 bundles of ens and 9 singles.
- Give them practice with some more 2 digit numbers.

## EXPLORE

**I) Stick game (or) Beads in a string:**

As an extension of the previous activity, to represent 3-digit numbers.

Eg.

- 43 is made with 4 bundles of tens and 3 singles.
- 243 is made with 2 groups of 10 bundles of 10 (i.e. a hundred group), 4 bundles of tens and 3 singles.
- 243 is made with 2 groups of 10 bundles of 10 (i.e. a hundred group), 4 bundles of tens and 3 singles.
- Then ask the students to make 243 using only bundles of tens and singles (i.e. 24 bundles of tens and 3 singles)
- Give them practice with other 3-digit numbers.

As an extension of the previous activity, now students will be asked to make 3 digit numbers and their expanded form.

**II) Units Tens Hundreds (UTH) Activity:**

Ensure that students are familiar with UTH to represent numbers.

### For Example:

- 74 is made with 7 Tens and 4 Units.
- 74 can also be made with 74 Units.
- 174 is made with 1 Hundreds 7 Tens and 4 Units.

*Note to Teachers: **Emphasize that making 74 with 74 Single Units is difficult and compare this with the convenience of using 7 Tens and 4 Units. Highlight that there are still the same number of blocks.*

*Then ask the students to make 174 using only Tens and Units. (17 Tens 4 Units)*

*[Note:* *These* *are the **following **ways* *in** whichstudentscouldmake 174]*

*et us make it a little more interesting with reater numbers. Let the students explore other umbers. Teacher has to guide students ppropriately.*

## EXPLAIN

Start with debriefing of the activity carried out using stick bundles / beads. Students could share their experiences and difficulties faced.

**Number expander activity:**

By now, students are probably in position to explain a 3-digit number. They also need to read and write. For this, the number expander activity will be useful.

Since number expander activity gives hands-on experience for students, it will be useful for them to relate the 3-digit concepts with their prior knowledge and improve their thinking capacity.

*Note to Teacher How to make number expander:*

*Take**a long strip of chart, divide it into 6 parts and mark as (Hundreds /Tens/Ones) in the piece of**chart as shown below.**Write a 3-digit number as shown below*

*Fold the chart so that Hundreds Tens and Ones are hidden as shown below*

umber with Hundreds, Tens and Ones. It coulde unfolded in the following ways tell this verbally without writing the number)*Now, students will unfold the chart to see the n*

- How will the shopkeeper write the amount in the bill? (Students could be asked to write the amount in number and words like how they usually do in bills)
- Now, you pay for the item (Demonstration / role play could also be done using currencies – hundred rupee notes, ten rupee notes and one rupee coins)

**EVALUATE**

Teacher can use oral and written tests to evaluate students understanding of the concept.

**To Download the Teaching Learning Material(TLM), Please click the link: ****Teaching Learning Material**

**Term: **
Term 2

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