1,2:1,11:6,29:17,38:23, ()

1,2:1,11:6,29:17,38:23, ()

1,2:1,11:6,29:17,38:23, (56:35)

Find the law 1 + 1 2 + 3 3 + 5 4 + 7 1 + 9 2 + 11 3 + 13 4 + 15 1 + 17 How much and how much is the 1998 number? Help!

2+3995
The first number is four groups of one cycle 1 + 1 2 + 3 3 + 5 4 + 7, then 1 + 2 + 3 + 4 + 4 + 1 + 2 + 3 + 4 + 4 + 4 + 4 + 4 + 4 + 4 + 4 + 1 + 2 + 3 + 3 + 4 + 4 + 1 + 1 2 + 3 + 3 + 4 + 4 + 1 + 1 2 + 3 + 3 + 4 + 4 + 1 + 2+
The last one is a continuous odd number 1 3 5 7 9 11 13 15 17
The number 1998 is 2N-1, which is 3995

The law of finding rules in grade one of primary school: 11-9 = 213-9 = 414-9 = 515-9 = 617-9 = 8 minus 9

Ten minus nine is a few plus one
For example, one plus one equals two
Thirteen minus nine is three plus one equals four

The law is 1 35 9 17 31 51 ()

1 3 5 9 17 31 51 （105 )
Is the question wrong
It should be 51.57
Rule: this number is equal to the sum of the three numbers in front of it
1+3+5=9
3+5+9=17
5+9+17=31
9+17+31=57
17+31+57=105

(1) (6) (16) () (51) (76) （1) (6) (16) ( ) (51) ( 76) （ ) ( ) (21) ( ) (35) ( ) (8) (15) (10) (13) (12) (11) ( ) ( )

(1) (6) (16) (31) (51) (76) 1 + 5 = 66 + 10 = 1616 + 15 = 3131 + 20 = 5151 + 25 = 76 (7) (14) (21) (28) (35) (42) 1 * 7 = 72 * 7 = 143 * 7 = 214 * 7 = 285 * 7 = 356 * 7 = 42 (8) (15) (10) (13) (12) (11) (14) (9) odd term: 8 + 2 = 1010 + 2 = 1212 + 2 = 1

If you can do simple calculation, you should do it simply; [2 / 17 + 1 / 3] / 5 / 51 5 of 12 ／ [5 of 12 ／ 1 of 3] 3 of 4 ／ 14 of 10 ／ 6 of 25 ＋ 3 of 4 + 5 × 25 of 6 Fill in the blank; 6 × [] = 0.5 = [] 24 = []:]

5 / 12
=5 of 12 ÷ 5 of 12 × 1 of 3
=1×1/3
=1/3
3 / 4 / 14 / 9 / 10
=3/4÷9/10÷14
=3/4×10/9×1/14
=1/84
6 of 25 ÷ 3 of 4 + 5 of 3 × 6 of 25
=6/25×4/3+5/3×6/25
=6/25×（4/3+5/3）
=6/25×3
=18/25
Fill in the blank; 6 × [12] = 0.5 = [48] 24 = [1]: [2]

1÷2,1÷5,1÷10,1÷17,( ),( ) …… Fill in the numbers according to the rules 1÷2,1÷5,1÷10,1÷17,( ),( ) …… Find the rules and fill in the numbers quickly

1÷26

In the brackets below, fill in the appropriate numbers 10, 20, 21, 42, 43, (), (), 174

10. The results showed that: 20, 21, 42, 43, 86, 87, 174; the law was: 2 + 1 * 2 + 1 * 2 + 1 * 2

There are several math problems I hope to help solve 1. A company plans to buy a batch of light bulbs, 11W ordinary energy-saving bulbs consume 110 kwh / 10000 h, unit price is 20 yuan; 5W LED bulbs consume 50 kwh / 10000 hours, unit price is 110 yuan. If the service life of both bulbs is 5000 hours, the price of each kilowatt hour is 0.5 yuan. How many times of the total cost of LED bulbs per 10000 hours is the ordinary energy-saving bulbs? 2. A shopping mall held an annual profit giving activity. If a single commodity is 300 yuan less than 180 yuan, 200 yuan less than 100 yuan, and 100 yuan less than 40 yuan; if not participating in the activity, a 5.5% discount will be given. How much does Xiao Wang need at least to buy a commodity worth 360 yuan, 220 yuan and 150 yuan each? 3. Now the time is 4:13 and 7:11. What angle does the hour hand and minute hand form? 4. The length of the river track is 120 meters, the current speed is 2 meters / second, the speed of ship a is 6 meters / second, and the speed of ship B is 4 meters / second. There are two round trips in the race. A and B start from the starting point at the same time and sail along the water first. How many seconds will a and B meet face-to-face for the second time?

1. The service life of all kinds of light bulbs is 50 hours, and two bulbs are used
Bulb cost: ordinary 20 × 2 = 40 yuan
Led 110 × 2 = 220 yuan
Power consumption cost: ordinary 110 × 0.5 = 55 yuan
Led 50 × 0.5 = 25 yuan
Total cost: ordinary 40 + 55 = 95 yuan
Led 220 + 25 = 245 yuan
245 △ 95 = 49 / 19 ≈ 2.58 times
2. For goods with 360 yuan, take part in the activity of reducing 180 yuan from 300 yuan
Actual need 120 + 60 = 180 yuan 180 △ 360 = 0.5, enjoy 50% off
220 yuan and 150 yuan goods together to do 300 minus 180 yuan activity
The actual demand is 120 + 70 yuan = 190 yuan 190 ÷ 370 ≈ 0.514, and the actual enjoyment is 5.2%
If 220 yuan goods participate in 200 minus 100 activities
If you do not participate in the activity, you need to:
100 + 20 + 150 × 0.55 = 202.5 yuan 202.5 > 190
So the minimum cost is 180 + 190 = 370 yuan
3. 13 and 11 / 7 = 150 / 11, 4:13 and 11:7 = 4 + 150 / 11 × 60 = 93 / 22
Minute needle for a circle of 360 degrees, 60 minutes
So at 4:13 and 7:11, the angle between the minute hand and the vertical line is:
360 / 60 × 150 / 11 = 900 / 11 degrees
One circle of the clock is 360 degrees for 12 hours
So at 4:13 and 7 / 11, the angle between the hour hand and the vertical line is:
360 / 12 × 93 / 22 = 139511 degrees
So the angle is 1395 / 11-900 / 11 = 45 degrees
4. At the same time, it takes time for a to complete a one-way trip: 120 × (6 + 2) = 15 seconds
At this time, B walked: 15 × (4 + 2) = 90 meters
In the remaining 30 meters and line, a against the water, B along the water
The time needed for the first meeting is 30 × [(6-2) + (4 + 2)] = 3 seconds
At this time, B walked (15 + 3) × (4 + 2) = 108 meters, 12 meters away from the first turning back point
12 △ (4 + 2) = 2 seconds
The distance between the first encounter a and the starting point is 108 meters
The time for a to return to the starting point is 108 × (6-2) = 27 seconds
When a returns to the starting point, B leaves the first turning back point 27-2 = 25 seconds
At this time, B has already walked 25 × (4-2) = 50 meters
Re encounter time (120-50) / [(6 + 2) + (4-2)] = 7 seconds
Therefore, the total time of the second face-to-face encounter is as follows:
15 + 3 + 27 + 7 = 52 seconds

A few math problems, very few! Hope to help me solve! 1. If a project is to be done alone, it will take 30 days for Party A, 20 days for Party B and 15 days for Party C. now, it will take five days for Party B and C to work together. How many days will it take for the remaining three people to work together? 2. There are two barrels of oil a and B. a barrel contains 10 kg of oil. If one third of the oil is given to a barrel from all over the barrel, the two barrels of oil will be the same weight. How many kilograms of oil was originally filled in barrel B? 3. Five eighths △ 5 means () 4. 5 kg salt and 100 kg water are made into brine, the ratio of salt water to water weight is (), the ratio of salt to salt weight is (), the ratio of salt to salt water is (), and the weight ratio of water drinking brine is () 5. Divide 240 into three numbers: A, B and C according to 4:7:5

1 (1-5 / 20-5 / 15) / (1 / 30 + 1 / 20 + 1 / 15) = 35 / 9 is about 3 days
2. Set B barrel with original oil X
10+1/3x=2/3x
x=30
4 21/20
20/1
1/21
20/21
5 105