A number with (1)B less than 2.8 is () represented by a formula containing letters.
(2)m× 1 is expressed as () in a simple way.
(3) In short, a×a×5 is ().
(4) The multiplicative associative law expressed by letters is ()
(5) The mall sold 30 refrigerators in the morning, one more in the afternoon, and one more in the afternoon ().
(6) Five A minus the product of 0.6 and 3, and the difference is ()
(7) The upper bottom of the trapezoid is a, the lower bottom is b, and the height is h area (S=).
(8) 38t cement shall be transported to the construction site, and each vehicle shall transport a(t), B times, * * * cement (t) and remaining cement (t).
(9) It is known that a=5, b=0.4, c=2. 1, and the value of formula 3a-6b+2c is ().
(10) Three consecutive integers, the middle one is n, and the other two integers are () and ().
Second, judge the following questions, draw "√" for the right and "×" for the wrong.
( 1)92=9×2= 18( )
(2) An equation containing letters is called an equation. ( )
(3) The meaning of solving the equation is the same as that of the solution of the equation. ( )
(4) V represents vehicle speed and T represents driving time, so vt not only represents the relationship between speed, time and distance, but also represents distance ()
Choose the correct answer and put the serial number in brackets.
( 1)5x-0.2×7 [ ]
A. this is an equation
B.it is not an equation, nor is it an equation.
C.this is an equation
(2) The sum of 5 times of A and B is expressed as [] by a formula containing letters.
A.(a+b)×5
B.a+5b
C.5(a+b)
(3)x÷0. 1=0. 1, and the solution of this equation is [].
A.x= 1
B.x=0.0 1
C.x=0. 1
(4) The number of 5' s more than 3 times of x is 36. The error of the listed equation is []
A.3x=36-5
B.3x+5=36
C.3x-5=36
Fourth, solve the equation
(1)5.4x+8= 18.8 (write out the inspection process)
(2)0. 12×5-5x=0. 1
(3) 13.5-6x=4.5
(4)8.4x-6x=7.2
5. Use the letter formula to calculate the area below.
(1) The base of the triangle is 2.4m long and 0.5m high.
(2) The base of parallelogram is 8.5cm long and 4.2cm high.
Six, column equation, find the solution of the equation.
(1) The number 3.2 more than x is 15.8.
(2) A number multiplied by the product of 2.4 and 3.6, and the sum is 28.64. Find this number.
Seven, column equation to solve application problems
(1) Xiaoming bought eight seedlings, paid 50 yuan and brought them back to 22 yuan. How much is each seedling?
(2) There is a parallelogram lawn in the school, with an area of 504m2, its height is 3 1.5m, and how long is its base?
(3) Two trucks * * * transport 70t of coal, and the coal transported by the other truck is 1.8 times that of the second truck. How many tons of coal do the two trucks transport?
(4) Light travels at a speed of 300,000 kilometers per second, which is about 7 times the length of the equator of the earth and more than 20,000 kilometers. What is the length of the earth's equator?
(5) The tractor factory plans to produce 7020 tractors, which will be produced for 6 days as planned, then 480 tractors a day, and then 9 days, just finishing the production task. How many tractors will be produced every day in the first six days?
(6) The distance between the two ports is 5 13km, and two warships start from both ports at the same time. After 4.5 hours, the distance between the two warships is still 72 kilometers. Assuming that warship A travels 48 kilometers per hour, how many kilometers does warship B travel per hour?