P3 数学 真题样题

正确答案：B. ∠a and ∠b

考点角：辨认锐角 · Angles: identifying acute angles

思路：锐角比直角小。用书角（直角）去比：∠a 和 ∠b 都比直角小，是锐角；∠c 和 ∠e 比直角大，是钝角；∠d 差不多是直角，不算锐角。所以选 ∠a 和 ∠b。
Think: An acute angle is smaller than a right angle. ∠a and ∠b are smaller than a right angle. ∠c and ∠e are bigger. ∠d is about a right angle.
小提醒：可以用一张纸的直角去比一比。
Tip: Use the corner of a piece of paper to compare.

正确答案：D. 1050 mℓ

考点容量：读量杯刻度并求和 · Volume: reading beaker scales and adding

思路：刻度从 0 到 1 ℓ（1000 mℓ）共 20 小格，每小格 50 mℓ。A 的水到第 5 格：5 × 50 = 250 mℓ。B 的水到第 16 格：16 × 50 = 800 mℓ。合起来 250 + 800 = 1050 mℓ。
Think: 1 ℓ = 1000 mℓ is split into 20 marks, so each mark is 50 mℓ. A: 250 mℓ. B: 800 mℓ. Total 1050 mℓ.
小提醒：先算每一小格是多少。
Tip: First find what one small mark stands for.

正确答案：B. 20 cm

考点周长：长方形的周长 · Perimeter: perimeter of a rectangle

思路：周长是一圈的长度。6 + 4 + 6 + 4 = 20 cm。
Think: Perimeter is the distance all the way around. 6 + 4 + 6 + 4 = 20 cm.
小提醒：24 是面积的数（6 × 4），不要和周长搞混。
Tip: 24 is the area (6 × 4), not the perimeter.

正确答案：B. AC // FG

考点平行线与垂直线：在方格中辨认 · Parallel and perpendicular lines on a square grid

思路：在方格上数步数。AC 从 A 往右 4 格、往下 4 格到 C；FG 从 F 往右 4 格、往下 4 格到 G。两条线方向完全一样，所以 AC // FG。
Think: Count squares. From A to C: 4 right and 4 down. From F to G: 4 right and 4 down. Same direction, so AC is parallel to FG.
小提醒：// 表示平行，⊥ 表示垂直（成直角）。
Tip: // means parallel; ⊥ means perpendicular (meeting at a right angle).

正确答案：B. 70 cm

考点周长：由相同长方形组成的图形 · Perimeter of a figure made of identical rectangles

思路：下面的长方形长 15 cm。上面三个长方形并排也是 15 cm，所以每个宽 15 ÷ 3 = 5 cm，长 15 cm。整个图形宽 15 cm，高 15 + 5 = 20 cm。周长 = 15 + 20 + 15 + 20 = 70 cm。
Think: The bottom rectangle is 15 cm long. Three rectangles fit across 15 cm, so each is 5 cm wide and 15 cm long. The figure is 15 cm wide and 15 + 5 = 20 cm tall. Perimeter = 15 + 20 + 15 + 20 = 70 cm.
小提醒：周长只算外面一圈的边。
Tip: Perimeter is only the distance around the outside.

正确答案：B. 110

考点条形图：读出横向条形的数值 · Bar graphs: reading the value of a horizontal bar

思路：找到 3C 那一条，它的末端对着横轴上 100 和 120 中间的刻度，就是 110 本。
Think: Find the bar for 3C. Its end lines up with the mark halfway between 100 and 120, which is 110.
小提醒：每一小格是 10 本书。
Tip: Each small mark on the scale stands for 10 books.

正确答案：A. 1

考点直角：辨认图形中的直角 · Angles: identifying right angles in a figure

思路：用直角（像书本的角）去比。左上和左下的角比直角小；右上、右下两个角和中间凹进去的角都比直角大；只有最右边尖角刚好是直角。所以 1 个。
Think: Compare each angle with a right angle (like the corner of a book). Only the angle at the right tip is exactly a right angle. So the answer is 1.
小提醒：可以用纸的角去比一比。
Tip: Use the corner of a sheet of paper to check.

正确答案：D. 4 kg 800 g

考点质量：读秤的刻度（每小格 200 g） · Mass: reading a scale where each small mark is 200 g

思路：0 到 2 kg 之间有 10 小格，所以每小格是 200 g。指针过了 4 kg 又走了 4 小格：4 × 200 g = 800 g。所以是 4 kg 800 g。
Think: There are 10 small marks between 0 and 2 kg, so each mark is 200 g. The pointer is 4 marks after 4 kg: 4 × 200 g = 800 g. So the mass is 4 kg 800 g.
小提醒：先算每一小格代表多少。
Tip: First find out how much one small mark stands for.

正确答案：A. 32

考点条形图：读图并比较 · Bar graphs: reading values and finding the difference

思路：走路的有 80 人。坐火车的柱子比 40 高 2 小格，每小格是 4，所以是 48 人。80 − 48 = 32。
Think: 80 students walk. The train bar is 2 small lines above 40. Each small line is 4, so it is 48. 80 − 48 = 32.
小提醒：先看清每一小格代表多少（这里是 4）。
Tip: First find what each small line stands for (here it is 4).

正确答案：B. BC and GF

考点平行线：在方格上辨认平行线 · Parallel lines: identifying parallel lines on a grid

思路：B 和 C 在同一条横格线上，所以 BC 是横线；G 和 F 也在同一条横格线上，GF 也是横线。两条横线永远不会相交，所以 BC 和 GF 平行。
Think: B and C are on the same grid line, so BC is a straight across line. G and F are also on one grid line. Two across lines never meet, so BC and GF are parallel.
小提醒：在方格上，两条线如果走的格数方向一样，就是平行线。
Tip: On a grid, lines going the same way the same number of squares are parallel.