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Second grade math darts book 2.
(1) Target1:1/3; 1/3; 1/3。 Goal 2:1/2; 1/4; 1/4。

(2)2/3; ?

(3)3/4。

Test analysis: First, find out the percentages of A, B and C in the two pictures.

(1) Target 1: The areas of A, B and C in the triangle are equal; The probability of throwing darts into areas A, B and C is 1/3, 1/3 and 1/3 respectively, and the areas of A, B and C in the circle account for 1/2, 1/4 and/kloc-0 respectively.

Goal 2: The probability of throwing darts into areas A, B and C is1/2; 1/4; 1/4;

(2) In the target 1, darts are thrown in area A or area B, that is, the percentage of the sum of areas A and B in the total area: 2/3;

(3) In Target 2, the probability that darts are not thrown in Zone C, that is, the probability that they are thrown in Zone A and Zone B is 3/4.

Comments: The probability problem is not difficult. Examining students' mastery of simple geometric probability not only avoids the practice of relying solely on formula mechanical calculation, but also embodies the application of mathematical knowledge in real life and even entertainment, and embodies the foundation of mathematics discipline. The knowledge points used are: probability = the ratio of corresponding area to total area.