NCERT Solutions for Class 4th Maths Chapter 6 Measuring Small Things — Let Us Do
Book page 85 to 89 Updated on2026-09-19
Q1.
Measure each object using a scale.
Answer
How to measure:
Put the 0 mark of the scale exactly at one end of the object.
Keep the scale straight along the object, next to the dotted red line the book draws.
Read the number at the other end. That number is the length in cm.
For the tall green carton, measure along the dotted line down its front edge.
The four objects on page 85 laid against a centimetre scale.
Sample answer (measured on the printed page):
Object
Length
Eraser
4 cm
Pencil
10 cm
Comb
10 cm
Tall green carton
11 cm
Why it happens: A scale measures the distance from 0.
If you start at 1 instead of 0, every answer comes out 1 cm short.
Tip: Measure in your own book too. If your answer is 1 cm away from ours,
check that the 0 mark was really at the end of the object.
Q2.
Write the names of the objects in increasing order of length.
Answer
The four objects on page 85 laid against a centimetre scale.
Increasing order means from the shortest to the longest.
eraser 4 cm pencil 10 cm comb 10 cm
carton 11 cm
4 is the smallest, then 10, then 10, then 11
Sample answer:
Eraser
Pencil
Comb
Tall green carton
4 cm
10 cm
10 cm
11 cm
Why it happens: Once every object has a number in the same unit, we simply
put the numbers in order from small to big.
Tip: The pencil and the comb come out nearly the same, about 10 cm. So they
may swap places. Measure both very carefully before you write them down.
Q3.
Estimate the lengths of the following and compare your responses with your friends, in the grade. Write some examples of things that can be lesser than or equal to 1 cm in length. Verify by measuring.
Answer
This is the table as it is printed in your book:
Length of items
Equal to 1 cm
More than 1 cm
Less than 1 cm
Actual measurement
A fingernail
An eraser
An ant
A grain of wheat
A rajma seed
Sample answer (first tick your guess, then measure and fill the last column):
Length of items
Equal to 1 cm
More than 1 cm
Less than 1 cm
Actual measurement
A fingernail
✔
about 1 cm
An eraser
✔
about 4 cm
An ant
✔
less than 1 cm
A grain of wheat
✔
less than 1 cm
A rajma seed
✔
about 2 cm
Things that are 1 cm long or shorter: a grain of rice, a mustard seed, a shirt button, a
staple pin, a chalk piece that is nearly finished, the head of a matchstick, a small bead.
Why it happens: One centimetre is about as wide as your little
fingernail. Anything that fits inside one gap on the scale is
less than 1 cm.
Tip: Lay the small thing on the scale from the 0 mark. If it does not reach
the 1 mark, it is less than 1 cm.
Q4.
Take three toy cars and find out how far each one can go. You can use a small wooden ramp, or you might like to make a ramp using any material that you have. Measure the distance each of your cars travels using measuring tape and write the answers in cm.
Answer
How to do it:
Rest one end of a board or a thick book on a pile of books to make a ramp.
Let the first car go from the top of the ramp without pushing it.
Mark where the car stops with a chalk dot.
Lay the measuring tape from the bottom of the ramp to the chalk dot. Read the cm.
Do the same for the other two cars, from the same spot on the ramp.
Rank 1 for the longest distance, then 2, then 3.
This is the table as it is printed in your book:
Car
Distance from the ramp
Rank
Car 1
_______ cm
Car 2
_______ cm
Car 3
_______ cm
Sample answer:
Car
Distance from the ramp
Rank
Car 1
85 cm
2
Car 2
120 cm
1
Car 3
60 cm
3
120 is the biggest, then 85, then 60
So Car 2 wins, Car 1 is second and Car 3 is third
Why it happens: Every car starts from the same place on the same ramp. So the
only thing that changes is the car, and the distance tells us which one rolls best.
Tip: 120 cm is more than a metre. You can also write it as
1 m 20 cm.
Q5.
Find the longest and the shortest route in this treasure hunt. You can go around the obstacles but cannot jump over them. You can only walk on the yellow tiles and not on the grass. Can you find the length of your route in centimetres? Look for the 1 cm clue in the map.The treasure-hunt map from page 87. The yellow squares are the tiles you may walk on, the green is grass, and the four coloured circles are the obstacles — the octopus, the lion, the hippo and the snake. The small red square is the 1 cm clue.
Answer
The map in your book: a green island covered with a grid of small squares. Yellow
tiles wind through the grass from the word START at the bottom to the treasure chest in the
middle. An octopus, a lion, a hippo and a snake sit on the way. In the top corner a small red square
is marked 1cm across and 1cm down — that is the clue.
How to find the length of your route:
The clue says every small square of the grid is 1 cm long on each side.
Draw your route with a pencil, staying on the yellow tiles only.
Count the squares your pencil crosses, one step at a time, going forward, back, left
or right.
The number of squares is the length of your route in centimetres.
How to count: each dot is 1 cm from the next, so every step of the route is 1 cm.
In the small picture above, the route goes
2 up + 2 right + 1 up + 3 right + 2 down + 2 right
2 + 2 + 1 + 3 + 2 + 2 = 12
So that route is 12 cm long
Count your own route on the book's map in exactly the same way. The shortest route is
the one that uses the fewest squares. The longest route is the one that winds all round the
island before reaching the chest.
Why it happens: Each step of the route covers one 1 cm square. So counting
the squares is the same as adding 1 cm again and again.
Tip: Write the number of squares on each straight bit of your route first.
Then add those few numbers instead of counting all the squares at one go.
Q6.
Trace your hand on a piece of paper. Measure it using the scale. Length of my hand = ________ cm
Answer
How to do it:
Put your hand flat on a sheet of paper with the fingers together.
Hold the pencil straight up and draw all round your hand.
Lift your hand. Now place the scale on the drawing, with the 0 mark at the bottom of your
wrist line.
Read the mark at the tip of your longest finger. That is the length of your hand.
The traced hand measured against the scale, from the wrist line to the finger tip.
Sample answer: Length of my hand = 14 cm.
Why it happens: We measure the outline, not the hand itself, because the
outline lies flat and does not move while we read the scale.
Try this: Measure a friend's hand too. Hands are not the same size, so
the hand is not a good unit for everybody — but it is a handy one for you.
Q7.
Use your hand to estimate the measurement of any object. Convert into centimetres. Verify using the scale.
Answer
How to do it:
First find the length of your hand in cm (from the last question).
Lay your hand along the object, end over end, and count how many hands it takes.
To change hands into centimetres, add your hand length that many times.
Now measure the same object with the scale and compare.
This is the table as it is printed in your book:
Object
Number of hands
Estimate using hand
Actual measure using the cm scale
1. Length of my textbook
_______ cm
_______ cm
2. Height of my chair
_______ cm
_______ cm
3. Width of my desk
_______ cm
_______ cm
4. Height of a flowerpot
_______ cm
_______ cm
Sample answer (taking my hand as 14 cm long):
Object
Number of hands
Estimate using hand
Actual measure using the cm scale
1. Length of my textbook
2
14 + 14 = 28 cm
26 cm
2. Height of my chair
3
14 + 14 + 14 = 42 cm
44 cm
3. Width of my desk
4
14 + 14 + 14 + 14 = 56 cm
55 cm
4. Height of a flowerpot
1
14 cm
15 cm
Why it happens: The hand works like a short rope. We repeat it and add, just
as we repeated the 1 m rope to draw a 5 m line.
Tip: The estimate and the real measure will not match exactly, and that is
fine. A good estimate lands close to the real number.
Q8.
Ashwin's scale is broken. Can you help him to measure using this scale?
Answer
Ashwin’s two broken scales, with a card placed along each one.
Yes. A broken scale still works. We read the mark at both ends and take the difference.
First card (the dark one, on the upright scale):
Top end of the card is at the mark 8
Bottom end of the card is at the mark 14
Count on: 8 → 9 → 10 → 11 → 12 → 13 → 14
That is 6 jumps of 1 cm
Length = 14 − 8 = 6 cm
Second card (on the flat scale, where the numbers run 16, 15, 14 …):
One end of the card is at the mark 16
The other end is at the mark 12
Count back: 16 → 15 → 14 → 13 → 12
That is 4 jumps of 1 cm
Length = 16 − 12 = 4 cm
Why it happens: A scale measures the distance between two
marks. Starting at 0 is only a habit — it just makes the subtraction easy, because
anything take away 0 stays the same.
Try this: Cover the 0, 1 and 2 of your own scale with paper and measure your
pencil starting from 3. Subtract 3 at the end. You get the same length.
Q9.
Fill the blanks on the number line below appropriately.The number line on page 89, with three empty boxes.
Answer
This is the number line as it is printed in your book:
The number line on page 89, with three empty boxes.
The three blanks are 50 cm, 75 cm and 1/4 m.
Above the line the numbers go up in tens:
0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100
The second empty box sits on the mark between 70 and 80, at
75 cm
Below the line the same marks are named in metres:
25 cm is a quarter of 100 cm, so it is 1/4 m
The same number line with the three boxes filled in.
Why it happens: The top row and the bottom row show the
same distances in two units. 25 cm and 1/4 m stand at one place, so they must
be the same length.
Tip: 25, 50, 75, 100 is skip-counting by 25. That is 1/4 m, 1/2 m, 3/4 m,
1 m.
Q10.
The length of a board is 2 metres. Sonu has a decorative border sticker which is 20 cm long. How many such stickers are needed to cover the length of the board completely?
Answer
10 stickers.
Length of the board = 2 m
1 m = 100 cm, so 2 m = 100 + 100 = 200 cm
Each sticker = 20 cm. Put them end to end and skip-count by 20:
20, 40, 60, 80, 100, 120, 140, 160, 180, 200
We counted 10 jumps
So Sonu needs 10 stickers
Ten stickers of 20 cm each, laid end to end along the 2 m board.
Why it happens: Five stickers of 20 cm make 100 cm, that is one metre. The
board is two metres, so it needs five stickers twice over.
Tip: Always change both lengths into the same unit
before you compare. Here we changed metres into centimetres.