Guidance for preparing for the 22 community workers' exam: an effective digital method for quick calculation-multiplication

Introduction

Tianjin Community Worker Examination Network provides test skills for all candidates. Multiplication helps candidates to enrich their knowledge of preparing for the test and analyze their answering skills. More exciting content is in the recruitment of community workers!

In the test paper, the knowledge of examination and calculation is the part of data analysis. For most students, data analysis is not too difficult, but it is still very difficult to complete the corresponding questions within the specified time. In addition, the score of data analysis is large, which is a battleground for candidates in the line test, and calculation is the most important thing in data analysis. After studying our previous calculation methods, in fact, data analysis is not that difficult, but we are not proficient in the methods. Today, let's talk about the simple operation skills in data analysis-characteristic number method? Multiplication.

I. Introduction of methods

The general principle of effective digital multiplication is that only the first two significant digits are taken for operation in multiplication.

Second, the principle of multiplication of significant digits

1. Total rounding: When the third significant digits of two numbers are all , 1 and 2, the first two significant digits of two numbers are directly taken for calculation;

2. all-in: when the third significant digits of two numbers are all 8 and 9, both the second significant digits of two numbers are all 1, and the calculation is made;

3. one entry and one shed: when the third significant digit of two numbers does not fully meet the above situation, the first three significant digits of two numbers are directly observed, the third significant digit of the smaller number is rounded off, and the larger number changes in the opposite direction.

Third, the application environment

In the multiplication calculation, when the option gap is large (> 5%), which can be multiplied by significant numbers < P > Fourth, the method application

1.181.9? 312.6 = ()

A.39237b.4983c.56862d.66371

Answer C. Analysis: Observing two numbers, the third significant digits are 1 and 2 respectively, so according to the trade-off principle of effective digit multiplication-give up all, so 181.9? 312.6? 18? 31=558, choose the closest C.

2.68.61? 428.3 = ()

A.17693b.29386c.2184d.35872

Answer B. Analysis: Observing two numbers, the third significant digits are 6 and 8 respectively, so according to the principle of effective digit multiplication-one in one shed, two numbers directly observe the first three significant digits 686 and 428, the third significant digit of the smaller number 428 is rounded to 43, and the larger number 686 is reversed and rounded to 68, so 68.61? 428.3? 68? 43=2924, choose the closest B.

3.2781.7? 1.697 = ()

A.3912b.4231c.4566d.4721

Answer D. Analysis: Looking at the two numbers, the third significant digits are 8 and 9 respectively, so according to the trade-off principle of effective digit multiplication-all in, so 2781.7? 1.697? 28? 1.7=476, choose the closest D.

in 212, the total sown area of crops in a certain area reached 16,255,5 mu, up 4.6% year-on-year. Among the grain crops, wheat was 2,956,1 mu, a year-on-year increase of 67.7%; 937,7 mu of corn, a year-on-year increase of 3.1%; 215,1 mu of soybeans, a year-on-year increase of 76.6%; 326,6 mu of rice, down 7.7% year-on-year. Among the vegetable planting areas, there were 654,8 mu of tomatoes, up 6.7% year-on-year; 212,7 mu of peppers, down .7% year-on-year.

Question: In 212, the sown area of rice was about () ten thousand mu less than that in 211.

A.2.51 B.2.33 C.2.72 D.2.86

answer C. Analysis: The sown area of rice in 212 was less than that in 211 < P >, and the closest C was selected.

in 29, the number of domestic tourists was 877.82 million, an increase of 12% over the previous year; Domestic tourism revenue was 387.8 billion yuan, up by 1.1% over the previous year. The number of overseas arrivals was 97.91 million, an increase of 19.7% over the previous year; There were 84.47 million compatriots from Hongkong, Macao and Taiwan Province, an increase of 8.6% over the previous year. Among inbound tourists, the number of overnight stays was 36.8 million, an increase of 11% over the previous year. Foreign exchange income from international tourism reached 2.4 billion US dollars, up by 14.6% over the previous year. In 21, the number of people leaving the country reached 16.6 million, an increase of 36.8% over the previous year, of which 1.6 million went abroad for personal reasons, an increase of 44.9% over the previous year.

question: in 28, the proportion of people leaving the country for private reasons to those leaving the country at home was about ()

A.76% B.57% C.63% D.81%

Answer B. Analysis: only item B meets the requirements.

There is a certain error in the effective number method, so everyone should pay attention to the gap between the options when doing the questions. However, in most provincial and municipal public examinations, the gap between the options is generally large, so it can be directly used in multiplication calculation. Candidates should pay due attention to the gap when using it.

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