The following excerpt was copied  from www.BibleHelp.org

“Growth by multiplication is much more effective than growth by addition. Consider these two savings plans. In plan A, you add $100 to your savings every day for a month. In plan B, you put a penny into your savings on the first day, double your input the second day and continue to double the input for the whole month. Which of the two plans do you think would accumulate more money? If you chose plan B you were correct. Plan A would accumulate $3,000, but plan B results in $10,737,418. With multiplication, you can start with something very small and quickly develop into something very large.

The principles of multiplication and addition apply to world evangelism as well. There are two basic approaches of leading people to Christ. In one approach, all our energy is spent on evangelism and none on discipleship for the new believers. The other approach combines evangelism and discipleship. After a person has been led to the Lord, he is discipled to maturity and trained to lead others to Christ.

Addition happens in churches that preach the gospel message and weekly have new converts. Yet, once the people are saved, there is little or no spiritual follow-up. This often results in stagnation in the life of the new believer. Although the new believer is saved, he never learns to reproduce himself by leading others to Christ.

Churches that use multiplication techniques generally spend 20. 40% of their time on evangelism and the rest of the time on comprehensive discipleship. As a result not only is the church leading people to Christ the converts are also leading people to Christ. Each convert learns to multiply himself.”