Grade 3Math
0.1 and One TenthLine them up above and below the same number line
On a number line where 0 to 1 is split into 10 parts, we write decimals above and fractions below. Numbers that point to the same spot above and below, like 0.1 and one tenth, or 0.7 and seven tenths, are the same size.
The narration and the pictures are in Japanese. You can hear the same words that are used in class at a Japanese school.
- Video
- 1:39（6 scenes）
- Problems
- 3 problems
Open this lesson in Japanese（0.1と 10分の1）
Let's try
Write the math sentence in your notebook first, then open the answer.
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1Which decimal is the same size as 4/10: 0.6, 0.4, or 4?
Hint
The spot you reach by counting 4 divisions from 0 on the number line is 4/10. One division is 0.1 as a decimal.
Answer
It is 0.4. 4/10 is 4 of 1/10, and 0.4 is 4 of 0.1, so they point to the same spot on the number line.
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2Which is bigger, 0.6 or 8/10?
Hint
Compare 8/10 and 0.6 by how many divisions (0.1, 1/10) each one is.
Answer
8/10 is bigger. 8/10 is the same spot as 0.8, and it is to the right of 0.6. If you compare by how many 0.1s, 8 is more than 6.
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3Show 0.9 as a fraction.
Hint
0.1 and 1/10 are the same spot on the number line.
Answer
It is 9/10. 0.9 is 9 of 0.1. 0.1 and 1/10 are the same size, so 9 of 1/10 is 9/10.
Words in this lesson
- number line 数直線
- A straight line with marks on it that shows numbers. The farther right you go, the bigger the number.
- one division 1目もり
- The amount to the next mark. On a number line where 0 to 1 is split into 10 parts, it is 0.1, or 1/10 as a fraction.
- numbers of the same size 同じ 大きさの 数
- Numbers that point to the same spot on the number line. 0.7 and 7/10 are written differently, but they are the same size.
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).
- The official commentary on the Course of Study says to show decimals such as 0.1 and fractions such as 1/10 above and below the same number line, so that children can feel that they are numbers of the same size. If you write decimals above and fractions below the marks on a ruler or a measuring box together, your child can see that the same mark has two ways of writing.
- The spot for 1 is 10/10 as a fraction, and as a decimal it is 10 of 0.1 put together. As a number, both are 1, and the answer is written "1." Changing fractions whose denominator is not 10 (such as 1/4) into decimals is learned in 5th grade.