NCERT Solutions for Class 4th Maths Chapter 6 Fencing and Lacing — Fencing and Lacing

Book page 91 Updated on2026-09-19

Q1.
Bhola is making a boundary with bricks for his vegetable garden. Colour the bricks on the boundary. How many bricks will he need to make the boundary?
Answer

The picture in your book: a rectangular vegetable bed with rows of small plants inside it. A low wall of bricks runs all round the bed. On the far side the bricks are already laid and coloured red; Bhola is kneeling and placing one more. The rest of the wall is drawn in white, with dotted lines that show where each brick will go.

What to colour: only the bricks that make the wall all round the bed — the two long sides and the two short sides. The plants inside are not part of the boundary.

How to count the bricks:

  1. Start at one corner and go round the bed once, the same way all the time.
  2. Count the bricks on the first long side, then the second long side.
  3. Count the bricks on each short side.
  4. Add the four numbers. Do not count a corner brick twice.
long sidelong side
A plain top view of a brick boundary round a garden bed.
In the drawing above:
top long side = 9 bricks    bottom long side = 9 bricks
left short side = 4 bricks    right short side = 4 bricks
9 + 9 + 4 + 4 = 26 bricks

Count the bricks on the picture in your book in exactly the same way. The bed there is drawn in a slanting view, so the far bricks look smaller than the near ones — count one side at a time and mark each brick with your pencil as you count it.

Why it happens: The wall is a closed ring round the bed. Going round once and counting is the only way to be sure no brick is missed and none is counted twice.
Tip: The book tells us the word for this: the length of the boundary of an object or shape is called perimeter.
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