CBSE Class 4 Mathematics Chapter 11: Tables and Shares - NCERT Solutions

To find the different ways to plant 18 plants, we need to find pairs of numbers that multiply to give 18. These pairs are called factors.

One way is to arrange the plants in 2 rows with 9 plants in each row. This can be written as:

$$18\; =\; 2\; \backslash times\; 9$$

So, there are 2 rows with 9 plants each.

Another way is to arrange the plants in 3 rows with 6 plants in each row. This can be written as:

$$18\; =\; 3\; \backslash times\; 6$$

So, there are 3 rows with 6 plants each.

Other possible arrangements include 1 row of 18 plants, 6 rows of 3 plants, 9 rows of 2 plants, and 18 rows of 1 plant.

Bheema's shelf has 2 rows with the same number of jars in each row to hold 30 jars in total. To find the number of jars in each row, we divide the total number of jars by the number of rows:

$$30\; \backslash div\; 2\; =\; 15$$

So, there are 15 jars in each row.

We can think of other ways to make a shelf to keep 30 jars by finding different pairs of numbers that multiply to 30.

Possible ways to arrange 30 jars:

• 3 rows: If there are 3 rows, each row will have $30\; \backslash div\; 3\; =\; 10$ jars.
• 5 rows: If there are 5 rows, each row will have $30\; \backslash div\; 5\; =\; 6$ jars.
• 6 rows: If there are 6 rows, each row will have $30\; \backslash div\; 6\; =\; 5$ jars.
• 10 rows: If there are 10 rows, each row will have $30\; \backslash div\; 10\; =\; 3$ jars.
• 15 rows: If there are 15 rows, each row will have $30\; \backslash div\; 15\; =\; 2$ jars.
• 30 rows: If there are 30 rows, each row will have $30\; \backslash div\; 30\; =\; 1$ jar.

Students can draw shelves representing any of these arrangements. For example, a student could draw a shelf with 5 rows, and show 6 jars in each row.

We can create the table of 7 by adding the corresponding numbers from the table of 4 and the table of 3. This is because $4\; +\; 3\; =\; 7$.

Let's see how this works:

Table of 4:

• $4\; \backslash times\; 1\; =\; 4$
• $4\; \backslash times\; 2\; =\; 8$
• $4\; \backslash times\; 3\; =\; 12$
• $4\; \backslash times\; 4\; =\; 16$
• $4\; \backslash times\; 5\; =\; 20$
• $4\; \backslash times\; 6\; =\; 24$
• $4\; \backslash times\; 7\; =\; 28$
• $4\; \backslash times\; 8\; =\; 32$
• $4\; \backslash times\; 9\; =\; 36$
• $4\; \backslash times\; 10\; =\; 40$

Table of 3:

• $3\; \backslash times\; 1\; =\; 3$
• $3\; \backslash times\; 2\; =\; 6$
• $3\; \backslash times\; 3\; =\; 9$
• $3\; \backslash times\; 4\; =\; 12$
• $3\; \backslash times\; 5\; =\; 15$
• $3\; \backslash times\; 6\; =\; 18$
• $3\; \backslash times\; 7\; =\; 21$
• $3\; \backslash times\; 8\; =\; 24$
• $3\; \backslash times\; 9\; =\; 27$
• $3\; \backslash times\; 10\; =\; 30$

Table of 7 (by adding Table of 4 and Table of 3):

• $7\; \backslash times\; 1\; =\; (4\; \backslash times\; 1)\; +\; (3\; \backslash times\; 1)\; =\; 4\; +\; 3\; =\; 7$
• $7\; \backslash times\; 2\; =\; (4\; \backslash times\; 2)\; +\; (3\; \backslash times\; 2)\; =\; 8\; +\; 6\; =\; 14$
• $7\; \backslash times\; 3\; =\; (4\; \backslash times\; 3)\; +\; (3\; \backslash times\; 3)\; =\; 12\; +\; 9\; =\; 21$
• $7\; \backslash times\; 4\; =\; (4\; \backslash times\; 4)\; +\; (3\; \backslash times\; 4)\; =\; 16\; +\; 12\; =\; 28$
• $7\; \backslash times\; 5\; =\; (4\; \backslash times\; 5)\; +\; (3\; \backslash times\; 5)\; =\; 20\; +\; 15\; =\; 35$
• $7\; \backslash times\; 6\; =\; (4\; \backslash times\; 6)\; +\; (3\; \backslash times\; 6)\; =\; 24\; +\; 18\; =\; 42$
• $7\; \backslash times\; 7\; =\; (4\; \backslash times\; 7)\; +\; (3\; \backslash times\; 7)\; =\; 28\; +\; 21\; =\; 49$
• $7\; \backslash times\; 8\; =\; (4\; \backslash times\; 8)\; +\; (3\; \backslash times\; 8)\; =\; 32\; +\; 24\; =\; 56$
• $7\; \backslash times\; 9\; =\; (4\; \backslash times\; 9)\; +\; (3\; \backslash times\; 9)\; =\; 36\; +\; 27\; =\; 63$
• $7\; \backslash times\; 10\; =\; (4\; \backslash times\; 10)\; +\; (3\; \backslash times\; 10)\; =\; 40\; +\; 30\; =\; 70$

This method helps in remembering and constructing the table of 7 by using tables that are already known.