Some math problems. 20 points 20

*(1-1 4)=45 (pcs).

45 (1-2 11) = 55 (pcs).

60-55=5 (pcs).

60*1 4-5=10 (pcs).

I actually bought (10) robot cats.

2. I'm sorry, no.

14*13*2=m).

7. No.

2.Choose one from each group, a total of 120 species, and choose one from three groups, a total of 15 species.

5.To find the circumference of a circle, 2* round up and add 1 to get 82

7.If the cow produces x liters of milk per day, then (3*5+3x)3=(5*5+x)4 gives x=11 liters.

*(1-1 4)=45 (pcs).

45 (1-2 11) = 55 (pcs).

60-55=5 (pcs).

60*1 4-5=10 (pcs).

A: I actually bought 10 robot cats.

2. 6 people in the sixth grade group, 5 people in the fifth grade group, and 4 people in the fourth grade group, each group selects 1 person to participate in the model aircraft competition, with a total of (120) selections; If the three groups jointly elect a representative, there are (15) ways to choose one.

14*13*2=m) tree).

A: About 82 small cypress trees are planted.

7. If the cow produces x liters of milk per day, then (3 * 5 + 3x) * 3 = (5 * 5 + x) * 445 + 9x = 100 = 4x

x = 11 A: A cow produces 11 litres of milk a day.

Kindergarten to buy 60 toys, of which the robot cat accounted for 1 4 of the toys, because the money is not enough to buy, the result is less to buy some robot cats. This way the robot cat becomes 2 out of 11 of the total. I actually bought (10) robot cats.

6 people in the 6th grade group, 5 people in the 5th grade group, and 4 people in the 4th grade group, each group selects 1 person to participate in the model aircraft competition, with a total of (120) selections; If the three groups jointly elect a representative, there are (15) ways to choose one.

If you plant a small cypress tree every 1 meter, you will plant about 82 small cypress trees along the circumference of a radius of 13 meters.

3 days of milk production in 3 goats and 3 cows is equal to 4 days of milk production in 5 goats and a cow, and if a goat produces 5 litres of milk a day, then a cow produces (11) litres of milk in a day.

1.Is there anyone else participating in the class except for the 51 class, no is 1 62Obviously, because the unit "1" is the same, 5 6 7 103

Innumerable, column 61/420, 62/420, 63/420....69/420, 601/4200, 602/2400....699/4200....

Fill in the blanks to score, calculate, divide, and divide.

You're a student, right? It's not good to be lazy in this way. Help you once, not for example.

There were 36 students in the May 1st class who participated in the mathematics expert competition, and 6 of them won the first prize. What percentage of the total number of participants won the first prize? Sixth.

Ming Ming and Xiao Hua read the same storybook respectively, Ming Ming read 5/6 of this book, and Xiao Hua read 7/10 of this book. Which of them sees more?

Why? Five sixths is equal to fifty tenths of sixty, and seven tenths is equal to forty-two tenths of sixty, so it is obvious that there is a lot to see.

Think about it: How many fractions can you write that is smaller than 1/6 and larger than 1/7? Convert it. For example, 13/84, 25-27/168, 49-55/336, and so on.

2/3 of a meter can represent either 1 meter (2/3) or 2 meters (1/3).

Fill a vacancy. The addition and subtraction method of calculating different denominator fractions should pay attention to the first (through the denominator), and then (calculate the addition and subtraction), and the calculation result can be (approximate the denominator).

Obviously because 5 6> 7 10

Countless: 13 84 23 168 24 168 25 168 .

Addition and subtraction of molecules, simplification, simplification.

1. The opening is upward, and the axis of symmetry a -2 -2 can be obtained a 12. There is always a function of f(a+b)=f(a)·f(b), which can be taken as an example of "f(x)=a x".

When x 0 then 0 f(x) 1, then 0 a 1 then f(0)=1 is true.

x 0, f(x) 1 is of course true.

0 a 1, so f(x))) = a x is monotonically decreasing on r.

1. The axis of symmetry is less than or equal to -2 (-2a b) because the opening is increasing upwards to the left of the axis of symmetry.

You can only solve one problem!!