Far and Near
Class 5 · Mathematics
5 ideas in Class 5 Mathematics, explained in plain words, with games and quizzes to practise.
Millimetres and Centimetres
Part of: Small and long lengths
On a ruler, each centimetre is cut into 10 equal tiny parts. Each tiny part is 1 millimetre (mm), so 1 cm is 10 mm. A line of 3 cm 4 mm is 30 mm and 4 mm more, which is 34 mm. Millimetres help us measure very small things such as a seed, a screw or the thickness of a coin.
Why it matters. Many everyday things are smaller than a centimetre or fall between two centimetre marks. Without millimetres, children round off or guess instead of measuring exactly.
Try it in two minutes
- Give your child a ruler and ask them to count the small marks between 0 and 1 cm. There should be 10.
- Measure a rice grain, an eraser and a pencil tip in mm.
- Ask: how many mm is 2 cm 5 mm? Let your child say it as 20 mm and 5 mm more.
Try at home. Ask your child to find three small things at home, measure each in mm, and write each length in cm and mm too.
Kilometres and Long Distances
Part of: Small and long lengths
For long distances such as the way between two towns, metres give very big numbers, so we use the kilometre (km). The word kilo means thousand, so 1 km is 1000 m. A 2 km walk is 2000 m, and a 500 m stretch is half a kilometre.
Why it matters. Road signs, travel times and maps all use kilometres. Children who know that 1 km is 1000 m can compare and plan distances sensibly.
Try it in two minutes
- Pick a place near your home that is about 1 km away. Ask: how many metres is that?
- Ask your child how many 250 m walks would make 1 km.
- Together name one thing that is better measured in metres and one in kilometres.
Try at home. Ask your child to list three places and say whether the distance from home would be given in metres or kilometres.
Converting Between Units
Part of: Working with units
The same length can be written in different units. Since 1 m is 100 cm, 3 m 25 cm is 300 cm and 25 cm more, which is 325 cm. In the same way, 1 km is 1000 m, so 4 km 80 m is 4080 m. To go the other way, split the number: 725 cm is 700 cm and 25 cm, so it is 7 m 25 cm.
Why it matters. To compare, add or subtract lengths, both must be in the same unit. A common slip is writing 3 m 5 cm as 350 cm, because the 5 cm must be written as 05.
Try it in two minutes
- Tape a 1 m string on the floor and ask your child how many 10 cm pieces fit in it.
- Say 2 m 40 cm and ask for it in cm. Then say 330 cm and ask for it in m and cm.
- Ask your child to explain why 3 m 5 cm and 3 m 50 cm are not the same.
Try at home. Measure the length of a room with a measuring tape and ask your child to write it in cm and also in m and cm.
Adding and Subtracting Lengths
Part of: Working with units
Lengths are added like numbers, but only like units go together. For 2 m 70 cm + 1 m 60 cm, add metres (2 + 1 = 3 m) and centimetres (70 + 60 = 130 cm). Since 130 cm is 1 m 30 cm, the total is 4 m 30 cm. Another way is to change everything to cm: 270 + 160 = 430 cm. Subtraction works the same way, borrowing 1 m as 100 cm when needed.
Why it matters. Real tasks such as cutting cloth, laying cable or planning a trip need children to combine and compare lengths. Forgetting to carry or borrow between units is the most common error.
Try it in two minutes
- Cut two ribbons, say 1 m 40 cm and 1 m 80 cm, and ask for the total length.
- Ask your child to solve it in two ways, by splitting into m and cm and by changing all to cm.
- Cut a piece off a 3 m rope and ask how much is left.
Try at home. Ask your child to measure two pieces of string at home, then add and subtract them in m and cm.
Multiplying and Dividing Lengths
Part of: Working with units
If one cushion cover needs 1 m 25 cm of cloth, six covers need 6 times that. Multiply each part: 6 × 1 m = 6 m and 6 × 25 cm = 150 cm, which is 1 m 50 cm, so the total is 7 m 50 cm. Division is the opposite: a 12 m rope cut into 4 equal pieces gives 12 ÷ 4 = 3 m each. Cost problems work the same way: if 4 m of cloth costs ₹ 240, then 1 m costs 240 ÷ 4 = ₹ 60.
Why it matters. Buying cloth, cutting rope or planning road work uses repeated lengths and equal sharing every day. Children who see that lengths behave like numbers feel more confident in word problems.
Try it in two minutes
- Say a stick is 40 cm long. Ask how long 5 such sticks are when laid end to end.
- Take a 2 m string and ask your child to cut it into 4 equal pieces. Ask how long each piece is.
- Ask: if 3 m of ribbon costs ₹ 60, how much does 1 m cost?
Try at home. Ask your child to find the total length of 6 steps of the same size, after measuring one step in cm.
What your child will practise
- Adding and Subtracting Lengths: Jungle Puzzle (Clue Puzzle)
- Converting Between Units: Space Quest (Flip and Match)
- Kilometres and Long Distances: Number Quest (Collect the Answer)
- Millimetres and Centimetres: Jungle Sort (Sort It Out)
- Multiplying and Dividing Lengths: Ocean Puzzle (Clue Puzzle)
- Quiz: Adding and Subtracting Lengths (8 questions)
- Quiz: Converting Between Units (8 questions)
- Quiz: Kilometres and Long Distances (8 questions)
- Quiz: Millimetres and Centimetres (8 questions)