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在小学数学竞赛题中,有些较复杂的数学问题用一般方法直接求解比较困难,我们可先研究它的简单情况或部分情况,即“退回到1”找规律,进而变复杂为简单,变繁难为容易,实现快速、准确解题的目的。下面就该解题策略的运用举例加以说明,以飨读者。例1 a是由2000个9组成的2000位整数,b 是由2000个8组成的2000位整数,则 a×b 的各位数字之和为____。(2000年小学数学奥预赛 A 第7题)分析与解:被乘数 a 和乘数 b 都是2000位数,直接计算出乘
In the elementary school mathematics contest, some of the more complicated mathematical problems are more difficult to be directly solved by the general method. We can first study its simple situation or part of the situation, that is, “back to 1” to find the law, and then turn it into simple and complicated For easy, fast, accurate problem solving. The following problem solving strategy to illustrate the use of examples to readers. Example 1 a is a 2,000-bit integer consisting of 2000 9, and b is a 2000-bit integer consisting of 2,000 8s. The sum of the digits of a × b is ____. (2000 primary school Mathematical Olympiad A question 7) Analytical solution: the multiplicand a and multiplier b are 2000 digits, directly calculated by