Math practice for 13 year olds - page 330 of 434
Number of problems found: 8670
- Diameter 3962
The diameter of the atomic nucleus is 10 to -12cm. How many atoms would fit on a 1 mm line if they could be arranged close together? - Direction 3958
In the direction of Hradec Králové, a car left Prague at 8 hours at a 50 km/h speed. At 8 hours and 30 minutes, another car followed him at an average 70 km/h speed. How long will it take to catch up with the first car? - Rectangular 3957
The block with a rectangular base measuring 18 cm and 11 cm has a surface of 1,556 cm square. Calculate the height of the block. - Calculate 3956
The rotating cylinder has a diameter of 14 cm and a surface of 1,186.92 cm square. Calculate the height of the cylinder. - Dimensions 3950
Calculate the solid diagonal of a block whose dimensions are: a = 3cm, b = 5, c = 7cm. Find its volume as well. - Percents of percentages
Calculate: (a) 5% of 25% of 85 b) 4% of 20% of 1500 c) 83% of 20% of 25 d) 0.3% of 70% of 90 - Increase 3946
Increase number 160 by: a) 25% b) 30% c) 150%
- Determine 3945
Determine the sum of the square roots of the number 25. - Temperatures 3942
The following temperatures were measured every 6 hours from 6 to 24 hours: -2.2 C, 2.1 C, 5.4 C, 3.9 C, 0.7 C, -1.9 C, -3.8 C. Calculate the average temperature from 6 to 24 hours. - Area of a cube
Calculate the surface area of a cube if its volume is equal to 729 cubic meters. - Beginning 3930
Roland has 490 balls. If he gave 145 bullets to Marek, he would still have 100 more bullets than Marek. How many balls did Marek have at the beginning? How many shots do they have together? - Dimensions 3929
An aquarium has 64 * 50 * 45cm dimensions and is filled 5cm below the edge. How many liters of water are in an aquarium? How many square meters are needed to produce an aquarium? - Glass
How many glasses are needed to produce glass with a base of a regular 5-gon if one base triangle in the base is 4.2 square cm and the height is 10 cm? - Z9-I-4
Kate thought of a five-digit integer. She wrote the sum of this number and its half in the first line of the workbook. Write a total of this number and its fifth on the second line. She wrote a sum of this number and its one nines on the third row. Finall - Tunnels
Mice had built an underground house consisting of chambers and tunnels: • each tunnel leading from the chamber to the chamber (none is blind) • from each chamber lead just three tunnels into three distinct chambers, • from each chamber, mice can get to an
- Unknown 3922
16% of the unknown number equals the square root of the number 25. Find this unknown number. - Circumference 3919
Determine the diagonal of a square whose circumference is equal to 72 cm. - Average speed
What is the average speed you have to move around the world in 80 days? (Path along the equator, round to km/h). - Area and percents
Find what percentage is a smaller cube surface when the wall's surface area decreases by 25%. - Four-digit 3912
Create all four-digit numbers from digits 1,2,3,4,5, which can repeat. How many are there?
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