The significance of decimals in the second volume of the fourth grade of People's Education Edition begins with measuring the height of the podium table and the length of the class table. After measuring 1 meter, it was found that there were 1 decimeter and 2 decimeter respectively, so the question was raised: "What should I do if the meter is not enough?" This leads to the cause of decimal. "When measuring and calculating, it is often impossible to get integer results, so decimals are often used."
Are you familiar with this sentence? Because fractions are also generated when calculating, measuring and dividing things, it is often impossible to get integer results. At this point, I can't help asking, why do you have to learn decimals after learning fractions? Isn't it all because you can't get integer results? )
Look at the textbook example 1 again, and communicate the relationship between fractions and decimals with the help of the meter ruler: 1 decimeter corresponds to110 meter, which also corresponds to 0. 1 meter; 3 decimeters corresponds to 3/ 10 meter, 0.3 meter ...1/00 meter, or 0.0 1 meter ... and then summarizes that "denominator is 10, 1000. The counting units for decimals are one tenth, one hundredth and one thousandth ... Write 0. 1, 0.0 1, 0.00 1 ...