Grade 3Math
Long Lengths (km and Distance Along a Road)Tape measures, kilometers, distance along a road, and straight-line distance
We measure long things and round things with a tape measure. Even longer lengths are shown in kilometers (km). Let's also see the difference between "distance along a road" (michinori), measured along the road, and "straight-line distance" (kyori), measured in a straight line.
The narration and the pictures are in Japanese. You can hear the same words that are used in class at a Japanese school.
- Video
- 2:19（9 scenes）
- Problems
- 3 problems
Open this lesson in Japanese（長い 長さ（kmと 道のり））
Let's try
Write the math sentence in your notebook first, then open the answer.
-
1From home to the post office is 800 m, and from the post office to the station is 550 m. What is the distance along the road from home to the station, in km and m?
Hint
For the distance along the road, add the lengths along the road. Change 1000 m to 1 km.
Answer
800 + 550 = 1350, so it is 1350 m. 1000 m is 1 km, so it is 1 km 350 m.
-
2How many m is 3 km 8 m?
Hint
There are no numbers in the hundreds place and the tens place, so don't forget to write 0.
Answer
3 km is 3000 m, so 3000 + 8 = 3008, and it is 3008 m.
-
3Write the unit that fits in each ( ): mm, cm, m, or km. The length of a pencil: 17 ( ). The length of a pool: 25 ( ). The distance along a mountain road: 6 ( )
Hint
Estimate about how long each one is before you choose.
Answer
The pencil is 17 cm, the pool is 25 m, and the mountain road is 6 km.
Words in this lesson
- tape measure まきじゃく
- A ruler you can roll up, used to measure the length of long things and round things.
- kilometer (km) キロメートル（km）
- A unit for long lengths. 1 km is 1000 m. Kilo means 1000 times.
- distance along a road 道のり
- The length measured along a road.
- straight-line distance きょり
- The length measured by joining 2 places with a straight line.
For parents and guardians
- The names of lessons and the order of topics differ slightly between textbooks. This page follows the content of Japan's national curriculum guidelines (the Course of Study). mm, cm, and m are covered in the 2nd grade unit "Units of Length," and the units of weight g and kg in the 3rd grade unit "Units of Weight."
- Some tape measures have the 0 mark at the very tip of the tape, and some have it a little way in. Before measuring, check together where 0 is, and try measuring around a tree or the length of a room.
- In daily life, "distance along a road" (michinori) and "straight-line distance" (kyori) are often used without distinction, but in math they are distinguished. Comparing the length of a walking route in a map app (distance along the road) with the length of a straight line joining the two points on the map (straight-line distance) makes the difference easier to feel.