Class 06 To find the LCM of two given numbers by using number grid

 Class 06 

To find the LCM of two given numbers by using number grid

ACTIVITY 2 – PLAYING WITH NUMBERS

Objective: 

To find the LCM of two given numbers by using number grid. 

Materials Required: 

geometry box , Squared paper, tracing paper, cardboard sheets, colour pencils, , etc.

Procedure: 

Let us find the LCM of 12 and 18.

STEP 1: Take a 10 x 10 squared paper and write numbers from 1 to 100. Paste the number grid on a cardboard sheet.

STEP 2 : Put a tracing paper over the number grid and trace its boundary. Cut the tracing paper along the boundary drawn to get a square piece exactly of the same size as the number grid.

ACTIVITY 2 – PLAYING WITH NUMBERS

STEP 3:  Repeat the step 2 to get another square piece of tracing paper.

STEP 4: Now find the multiples of 12, which are 12, 24, 36, 48, 60, 72, 84, 96, ......

STEP 5 : Place one of the square pieces on the number grid and colour the squares which contain multiples of 12. 

Mark 1 on the tracing paper to identify the correct position of the tracing paper.

STEP 6: Remove the tracing paper.

ACTIVITY 2 – PLAYING WITH NUMBERS

STEP 7: Find the multiples of 18, which are 18, 36, 54, 72, 90, ......

STEP 8: Place another square piece on the number grid and encircle the multiples of 18 on the tracing paper. Mark 1 on the tracing paper to identify the correct position of the tracing paper.

STEP 9:  Remove the tracing paper.

ACTIVITY 2 – PLAYING WITH NUMBERS

STEP 10: Now place both the square pieces (figures 3 and 5) on the number grid (figure 1), such that these square pieces cover the 

number grid exactly,

Observations:

In STEP 5 , the shaded numbers are multiples of 12.

In STEP 8, the encircled numbers are multiples of 18.

In STEP 10, the numbers which are shaded and encircled are the common multiples of 12and 18, i.e., 36 and 72 common multiples of 12 and 18.

Now 36 is smaller than 72. Hence, LCM (lowest common multiple) of 12 and 18

Conclusion: 

From the above activity, we find that the LCM of 12 and 18 is 36.

Do Yourself: 

By activity method, find the LCM of:

1. 8 and 12 2. 3, 5 and 10 3. 2, 4 and 10 4. 4, 6 and 9