AMC 8 L1: Assignment

Complete problem set with solutions and individual problem pages

Problem 1 Easy

Calculate: 1+3+5+7+9+11+\cdots +29=            

Answer:225

~~~~~1+3+5+7+9+11+\cdots +29

=\left( 1+29 \right)\times 15\div 2

=225

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Problem 2 Easy

Calculate: 100-99+98-97+96-95+\cdots +2-1=            

Answer:50

~~~~100-99+98-97+96-95+\cdots +2-1

=1+1+1+1+\cdots+1

=1\times50

=50

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Problem 3 Easy

Calculate: \frac{1}{2}\times \frac{2}{3}\times \frac{3}{4}\times \cdots \times \frac{11}{12}=            

Answer:\frac1{12}

\frac{1}{2}\times \frac{2}{3}\times \frac{3}{4}\times \cdots \times \frac{11}{12}=\frac1{12}

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Problem 4 Medium

Suppose that A☆B means 3A-2B. What is the value of x if x☆ (4☆1) =7?

  • A.

    7

  • B.

    8

  • C.

    9

  • D.

    10

Answer:C

x☆ (4☆1) =x☆ (3\times 4-2\times 1) =x☆10=3x-20=7 \Rightarrowx=9.

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Related Paper
2014 AMC 8 AMC 8 L1: Calculation Tricks AMC 8 L2: Basic Geometry AMC 8 Daily Practice Round 11
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