AMC 8 L1: Calculation Tricks

Complete problem set with solutions and individual problem pages

Problem 7 Easy

Calculate: 100+99-98-97+96+95-94-93+\cdots +4+3-2-1=            

Answer:100

100+99-98-97+96+95-94-93+\cdots +4+3-2-1

=(100+99-98-97)+(96+95-94-93)+\cdots +(4+3-2-1)

=4\times25

=100