1、 ( 1+5/6)+ 2.29+ (6+ 1/6)+ 7.8 1
= 1+6+6/6 +2.2+7.9
= 8+ 10. 1
= 18. 1
2, 4.6 times (1+3/8)+8.4÷ 8/1-(1+3/8) x5.
= 4.6 times (1 1/8)+8.4 times (11/8)-(1/8) x5.
= ( 1 1/8)X(4.6 + 8.4 - 5)
= ( 1 1/8)X8
= 1 1
3、8/9 X[3/4-(7/ 16- 1/4)]
= 8/9 X[3/4-7/ 16+ 1/4]
= 8/9 X[ 1- 7/ 16 ]
= 8/9 X 9/ 16
= 1/2
4, 2.75 points [15X (2- 1/3+2.5)]
=(2.5+0.25)/[30-5+ 1.5x 25]
=(25x 0. 1 1)/[25+ 1.5x 25]
= 0. 1 1/ [ 1+ 1.5 ]
= 1. 1/ 25
= 4.4/ 100
= 0.044
5 、( 99+ 16/ 17)X34+(9 1/ 14 1)x 142
=( 100- 1/ 17)X34+(9 1/ 14 1)X( 14 1+ 1)
= 3400 -2 + 9 1 + 9 1/ 14 1
= 3489 + 9 1/ 14 1
Second, fill in the blanks.
1. We know that it takes about 5: 48: 46 in 365 days for the earth to revolve around the sun. If a year is 365 days, there will be (23) extra hours (15) minutes (04) seconds in four years.
4X(5+ 48/60 +46/3600)
= 4X(5+45/60+3/60+45/3600+ 1/3600)
= 20+ 180/60+ 12/60+ 180/3600+ 4/3600
= 20+ 3+ 12/60+ 3/60+ 4/3600
= 23+ 15/60+ 4/3600
2. The exchange rate shown in the foreign exchange quotation on a certain day is: US$ 65,438+0 for 8.4 yuan RMB. On this day, Mr. Wang exchanged $80 for 65,438+065,438+020,000 VND, 1 10,000 VND is about RMB (6).
Dollar 1 is converted into RMB 8.4 yuan, 80X8.4 =672 yuan, and RMB 672 is converted into Vietnamese dong 1 120000, so it is 672/ 1 12= 6 yuan.
3. A careless accountant paid more attention to the payable on the invoice issued by the shipper when sending money to the shipper, which increased the payable by 10 times. A few days later, the owner returned the 7020 yuan remitted by him in full, and the amount payable was (780) yuan.
Accounts payable became 10 times, an increase of 9 times. The original payable is 7020/ 9= 780 yuan.
4. In the array (1, 1, 1), (2, 4, 8), (3, 9, 27), 100, the sum of three numbers is (10655).
There are three numbers in each group, the first is a natural number, the second is a square number, and the third is a cubic number. The three numbers in the 1 00 group are 100, 1 0000 and 100 000.
5. The uphill speed of the car is per hour 12km, the downhill speed of the original road is 20km per hour, and the average speed back and forth is per hour (15km).
Up-hill trip 1, up-hill speed 12km/h, up-hill time112, down-hill speed 20km, down-hill time 1/20. The average round-trip speed is the total round-trip time divided by the total round-trip time, 2/(12+1/20) = 2/(5/60+3/60) =120/8 =1.
We can take the least common multiple to calculate the distance up and down the mountain. It takes 60/ 12= 5 hours, 60/20= 3 hours to go up and down 60 kilometers, and the average round-trip speed 120/8= 15 kilometers/hour.
6. 10 The same cubes with a surface area of 1 12 cm2 are stuck in a row, and the surface area of this cuboid is (784) cm2.
The surface area of a cube is the sum of the areas of six identical squares, and the area of each single side of each cube is 1 12/6 square centimeters. After being glued into a cuboid, the surface area of the cuboid is 2+40= 42 times that of this square, and the surface area of this cuboid is 42x 1 12/6 = 7x68.
Another method is to bond 10 cubes together, and subtract 18 square faces from 9 bonding surfaces to calculate the surface area of a cuboid, which is112x10-18x/kloc-0.
7. A cube, now its six faces are painted with red paint, and then it is divided into 27 cubes with a saw. Of these cubes, only (12) two sides are painted with red paint, only (6) one side is painted with red paint, and (1) one side is not painted with red paint.
The last question is too simple. Have you never played or seen the Rubik's Cube? 27 small cubes, that is, 3X3X3. Only the small cube with red paint on both sides is in the middle of the original cube edge. A cube has 12 sides, and only a small cube with two sides painted with red paint is 12.
If at the vertex position of the original cube, three faces of the small cube are painted with red paint, the cube has eight vertices, and the three faces of the small cube painted with red paint are eight. If it is in the middle of each face of the original cube, only one side of the small cube is painted with red paint, the cube has six sides, and only one side of the small cube painted with red paint is six. If it is in the center of the original cube, none of the last cubes will be painted with red paint.
27 small cubes, red paint on three sides+red paint on two sides+red paint on one side+no red paint = 8+ 12+ 6+ 1= 27.