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P1 maths・1M3

Length and distance (II)

The centimetre (cm); measuring the length of objects and the distance between two points with a ruler, including when the object does not start at 0; choosing a suitable measuring tool; and estimating lengths with ever-ready rulers such as the width of a thumb, the length of a foot or a hand span.

Key words

ChineseEnglish
厘米centimetre (cm)
間尺ruler
量度measure
估計estimate

The 4 short lessons and the chapter test

Lessons are in Chinese for now.

  1. 認識厘米尺
  2. 量度距離
  3. 揀選工具和永備尺
  4. 估計長度
  5. 章節測驗 (chapter test)

Sample questions (in Chinese)

Question 1這枝鉛筆長多少厘米?

0123456cm

cm

Answer and explanation

答案:5 cm

為甚麼?一端對準 0,另一端對準 5,所以長 5 厘米,寫作 5 cm。

Question 2這枝鉛筆沒有對準 0。它長多少厘米?

012345678cm

cm

Answer and explanation

答案:4 cm

為甚麼?一端對準 3,另一端對準 7。由 3 數到 7,共有 4 格,每格 1 厘米,所以長 4 cm。

Question 3兩點之間的距離是多少厘米?

012345cm

cm

Answer and explanation

答案:3 cm

為甚麼?一點對準 1,另一點對準 4。由 1 數到 4,共有 3 格,所以距離是 3 cm。

Question 4紙帶乙長 13 cm,紙帶甲長 8 cm。紙帶乙比紙帶甲長多少厘米?

長 cm

Answer and explanation

答案:長 5 cm

為甚麼?求相差多少,用減法:13 − 8 = 5,所以紙帶乙比紙帶甲長 5 cm。

Based on learning unit 1M3 of the Education Bureau’s Primary Mathematics Curriculum (2017).

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