According to the meaning of the question, the front of the car uses 8 wheels and each car uses 6 wheels.

There are 40 wheels, so:

40-8 = 32, that is, there are 32 wheels left besides the front wheel.

32/6=5……2

The remaining 32 wheels can be assembled into 5 cars, and the remaining 2 wheels.

So Mr. Liang has 40 wheels, eight of which are used for locomotives, and he can't assemble a 6-car train.

Extended data:

This kind of problem belongs to the remaining problems in mathematics.

The remainder has the following important properties (A, B and C are all natural numbers):

(1) The absolute value of the difference between the remainder and the divisor should be less than the absolute value of the divisor (applicable to the real number field);

(2) Dividend = divisor × quotient+remainder;

Divider = (dividend-remainder) ÷ quotient;

Quotient = (dividend-remainder) divider;

Remainder = dividend divided by quotient.

If the remainder of a and b divided by c is the same, then the difference between a and b can be divisible by c, such as 17 and 1 1, and the remainder is 2, then17-1can be divisible by 3.

(4) the sum of a and b divided by the remainder of c (unless there is no remainder) is equal to the sum of a and b divided by the remainder of c.

For example, if the remainder of 23 16 divided by 5 is 3 and 1, then the remainder of 23+ 16 divided by 5 is 3+ 1 = 4. Note: when the sum of the remainder is greater than the divisor, the remainder is equal to the sum of the remainder divided by the remainder of C.

(5) the product of a and b divided by the remainder of c is equal to the product of a and b divided by the remainder of c.

For example, if the remainder of 23 16 divided by 5 is 3 and 1, then the remainder of 23 times 16 divided by 5 is 3 times 1, that is, 3 times 1. Note: when the product of the remainder is greater than the divisor, the remainder is equal to the product of the remainder divided by the remainder of C.

Division arithmetic

(1) divided by the highest value of bonus;

(2) If the divisor is several numbers, look at the first few numbers of the dividend; If not, look at another number;

(3) Where should the division of quotient be written?

(4) The remainder of each division must be less than the divisor;

(5) After finding the highest part of the quotient, if the dividend is less than 1, write a 0 in that place.