When explaining this lesson, the teacher has clearly told the students how to compare sizes, and the textbook has also explained its rules: first, compare the integer digits of two numbers, and the larger the integer digits, the larger the integer digits. If the integer digits are the same, compare the decimal digits. . . And so on, the bigger the bigger. Obviously 7.80 1 < 7.8 1, 0.42 > 0.409, 7. 134 > 7. 13.

In the length unit, the forward speed between every two adjacent units is 10, from high unit to low unit, the forward speed is 10, and vice versa, so: 7 mm =0.7 cm =0.07 decimeter =0.007 meter.

7 cm =0.07 m

7 decimeters =0.7 meters