P5 数学 真题样题

正确答案：D. 511

考点分数：部分占整体的几分之几 · Fractions: fraction of a set

思路：一共有 3 + 5 + 3 = 11 颗星，涂色的有 5 颗，所以是 5/11。
Think: There are 11 stars and 5 are shaded, so the fraction is 5/11.
小提醒：分母是全部的数量。
Tip: The denominator is the total number of stars.

正确答案：A. 38

考点数据分析：圆形图与分数 · Data analysis: fractions from a pie chart

思路：尺子占直角，是 ¼。剩下 ¾ 是笔、铅笔和橡皮擦。笔 = 铅笔 + 橡皮擦，所以笔占 ¾ 的一半：¾ ÷ 2 = 3/8。
Think: Rulers take a right angle, which is 1/4. The other 3/4 is pens, pencils and erasers. Pens = pencils + erasers, so pens are half of 3/4: 3/4 ÷ 2 = 3/8.
小提醒：直角在圆形图里是 ¼。
Tip: A right angle in a pie chart is 1/4 of the whole.

正确答案：C. 214

考点分数：数线上的带分数 · Fractions: mixed numbers on a number line

思路：从 1½ 到 2½ 相差 1，分成 4 等份，每份是 ¼。A 在 1½ 后面第 3 格：1½ + ¾ = 2¼。
Think: From 1 1/2 to 2 1/2 is 1 whole, cut into 4 equal parts, so each part is 1/4. A is 3 parts after 1 1/2: 1 1/2 + 3/4 = 2 1/4.
小提醒：先算每一小格代表多少。
Tip: First find the value of each small part.

正确答案：D.

考点数据分析：表格与条形图对应 · Data analysis: matching a table to a bar graph

思路：Brian 最重（70），Gopal 第二（56），Kelly 第三（42），Ann 和 Dawn 一样高且最矮（28）。只有图 (4) 符合。
Think: Brian is the heaviest (70), then Gopal (56), then Kelly (42). Ann and Dawn are the same and the lightest (28). Only graph (4) shows this.
小提醒：比较柱子的高低顺序和哪些柱子一样高。
Tip: Check the order of the bar heights and which bars are equal.

正确答案：B. 44°

考点角：直线上的角与重叠部分 · Angles: angles on a straight line with an overlapping angle

思路：∠POS 和 ∠ROQ 加起来比 180° 多出的部分，就是重叠的 ∠ROS：100° + 124° − 180° = 44°。
Think: The two angles overlap at ∠ROS. 100° + 124° − 180° = 44°.
小提醒：直线上的角加起来是 180°。
Tip: Angles on a straight line add up to 180°.

正确答案：B. 16 55

考点时间：24 小时制与往前推算时间 · Time: 24-hour clock and finding an earlier time

思路：钟面是 5 点 20 分，选项用 24 小时制，就是 17 20。往前 25 分钟：17 20 → 17 00（20 分）→ 16 55（再 5 分）。
Think: The clock shows 5.20, which is 17 20 in the 24-hour clock. 25 min before: 17 20 → 17 00 → 16 55.
小提醒：分针指 4 是 20 分；时针在 5 和 6 之间是 5 点多。
Tip: Minute hand at 4 means 20 min; hour hand between 5 and 6 means after 5.

正确答案：A. AR

考点平行线：在方格纸上找平行线 · Parallel lines: identifying parallel lines on a square grid

思路：从 Q 到 P 是向右 1 格、向上 3 格。从 R 到 A 也是向右 1 格、向上 3 格，所以 AR // QP。
Think: Q to P goes 1 right and 3 up. R to A also goes 1 right and 3 up, so AR is parallel to QP.
小提醒：数“横走几格、竖走几格”，一样就平行。
Tip: Count across and up. Same moves mean parallel lines.

正确答案：A. 84 cm²

考点三角形面积：用底和对应的高求面积 · Area of triangle: using base and its perpendicular height

思路：三角形面积 = 1/2 × 底 × 高 = 1/2 × 14 × 12 = 84 cm²。
Think: Area of triangle = 1/2 × base × height = 1/2 × 14 × 12 = 84 cm².
小提醒：高是和底垂直的 12 cm，不是斜边 13 cm 或 15 cm。
Tip: The height is the 12 cm line at right angles to the base, not the slanting sides.

正确答案：D. 60%

考点百分比：图形中涂色部分的百分比 · Percentage: shaded part of a figure as a percentage

思路：一共 20 个小正方形，涂色 12 个。12/20 = 60/100 = 60%。
Think: There are 20 small squares and 12 are shaded. 12/20 = 60/100 = 60%.
小提醒：两行都要数，先求分数再化成百分比。
Tip: Count both rows, write a fraction, then change it to a percentage.

正确答案：B. BF

考点三角形：找底边对应的高 · Triangles: identifying the height for a given base

思路：以 AD 为底，高是从对面的顶点 B 向 AD 作的垂线，也就是 BF。
Think: With base AD, the height is the line from the opposite corner B that meets AD at a right angle. That is BF.
小提醒：高要从底边对面的顶点出发，并且与底边垂直。
Tip: The height starts at the vertex opposite the base and is perpendicular to the base.