1, there are 1 zeros at the end of the two multipliers, so there are at least two zeros at the end of the product. ( × )

2.( 18× 2)+(36÷ 3) After removing the brackets, the result remains unchanged. ( √ )

3. The operation sequence of all elementary arithmetic is multiplication and division before addition and subtraction. ( × )

4, 45+35 ÷ 5 with brackets becomes (45+35) ÷ 5, and the operation order has changed. ( √ )

5. 12×8=( 10+2)×8 here is the distribution law of multiplication. ( √ )

6.25× 2/kloc-0 /× 4 = 25× 4× 21Only the multiplicative associative law is used here. ( × )

7、 138+ 10 1= 138+ 100+ 1 ( √ )

8、22×99+99=22× 100 ( √ )

9. 1 is an odd number and a prime number. ( × )

10, all even numbers are composite numbers. ( × )

1 1 and 20 have six factors, and there are countless multiples of 20. ( √ )

12, a number is a multiple of 12, and this number must be a multiple of 3 and 4. ( √ )

13, the sum of two odd numbers is even, and the product of two odd numbers is composite. ( × )

14, a natural number has 0 digits, and this natural number must be a multiple of 2 and 5. ( √ )

15, the factor of a number is less than itself, and the multiple is greater than itself. ( × )

/kloc-multiples of 0/6 and 9 must be multiples of 3. A multiple of 2 must be a multiple of 4. ( × )

17, dividend and divisor are multiplied or divided by the same number (except 0) at the same time, and the quotient remains unchanged. ( √ )

18, if one factor is constant and another factor is multiplied or divided by a number (except 0), the product will also be expanded or reduced by the same multiple. ( √ )

19, because 75 ÷ 4 = 18...3, according to the invariant law of quotient, 750 ÷ 40 = 18...3.( ×)

20. When two numbers are divided, the dividend is expanded by 3 times, the divisor is reduced by 3 times, and the quotient is expanded by 9 times. ( √ )

2 1, because 360÷ 15=24, so 3600 ÷15 = 240,360 ÷ 5 = 8. ( × )

22、 13-3a= 10a ( ×)

23. The product of two digits multiplied by three digits may be three digits, four digits or five digits. ( × )

Space and graphics

1. Three ropes with lengths of 5cm, 5cm and 1 1cm can form an isosceles triangle. ( × )

2. A triangle with three equal angles must be an equilateral triangle, and an equilateral triangle is also an isosceles triangle. ( √ )

A triangle has at most one right angle. ( √ )

4. The sum of two acute angles must be greater than 90 degrees. ( × )

5. Right triangle and obtuse triangle have only one height. ( × )

6. A figure composed of three lines is called a triangle. ( × )

7. Divide a big triangle into two triangles of equal size, and the sum of the internal angles of each small triangle is 90. ( × )

8. The base angle of an isosceles triangle must be acute. ( √ )

9. An isosceles triangle is also an acute triangle. ( × )

10. A triangle with two acute angles must be an acute triangle. ( × )

1 1, an equilateral triangle must be an acute triangle. ( √ )

12, the upper angle of an isosceles triangle is called the vertex angle. ( √ )

13. Triangle can be divided into acute triangle, right triangle and obtuse triangle according to angle. ( √ )

14, triangles can be divided into isosceles triangles, equilateral triangles and arbitrary triangles according to their sides. ( √ )

15, only a set of figures with parallel edges is called trapezoid. ( × )

16, the square is a special rectangle, the rectangle is a special parallelogram, and the trapezoid is also a special parallelogram. ( × )

17, two isosceles trapezoid can be combined into a parallelogram. ( × )

18. Countless heights can be made from a vertex of a parallelogram to the opposite side. ( √ )

19, with two 8 cm and two 6 cm sticks, you can definitely make a parallelogram. ( √ )

20, a point on the parallelogram, can only be a high. ( × )

Statistics and measurement

1, a bottle of Wahaha has 180 liters. ( × )

Mingming drank 400 ml of milk today. ( √ )

The capacity of water bottle is larger than that of milk bottle. ( × )

4. 1 liter weight 1 kg. ( √ )

5. Drop 1 approximately 1 ml with a dropper. ( × )