Mao Siban (6)

Recently, we are learning approximate values. The teacher said it was a little difficult, but I think all the difficulties will be easily solved by us as long as we master the skills.

Example 1: Find the divisor of 539 180 in "ten thousand"? I use the method of "rounding" to calculate (if the highest digit of mantissa is 4 or less, the mantissa is discarded and each digit of mantissa is rewritten as 0; If the highest mantissa is 5 or more, you need to enter 1 in the first digit of the mantissa, and then rewrite each digit of the mantissa as 0). The number of digits in the highest mantissa of this number is 9(53-9 180), so advance one digit to 1, then the first digit of the highest mantissa becomes 4, and then all mantissas are rewritten as 0. After removing 5, the approximate number of 539 18 can be 540,000.

Example 2: Take "100 million" as the unit, find the approximate figure of 534 million? I still use "rounding" to solve the problem. First, the highest mantissa is 4(53-4000-0000). "4" can be directly discarded and replaced by "0", and all the next three levels are "0", so eight "0" can be replaced by "100 million". So the answer to this question is 5.3 billion.

Example 3: Find the divisor of 20680000000 in "100 million"? The highest digit of mantissa is "8" (206-8000-0000). Based on "rounding", if "8" is removed, the previous number becomes "1", 6 plus 1 becomes 7, and the last 8 zeros are replaced by 1 billion. The answer is: 20.7 billion.

Students, after listening to my explanation, you should know how easy it is to solve the divisor problem by rounding! It seems complicated, but in fact, you can easily find the answer with a little brain. Let's open the skylight of wisdom in our hearts and enjoy the infinite mystery of the mathematical world!