Maths practice for 12-year-olds - page 288 of 347
Number of problems found: 6923
- Cuboid - volume, diagonals
The length of the one base edge of cuboid a is 3 cm. The body diagonal is ut=13 cm, and the diagonal of the cuboid's base is u1=5 cm. What is the volume of the cuboid? - Ratio expressions
Write the ratio in 5 different ways: 4:12 - Speedboat and train
At 12:15, a train speeding 55 km/h left the station. Twelve minutes later, an 80 km/h speedboat set off behind the train. What time does the express train catch up? How far from the station? - Height ratio
In a general triangle, the aspect ratio a: b = 2:3. What is the ratio of heights va: vb? - Ratio
Write the ratio with other numbers so that the value is the same: 2:9 - Republic
First, guess which circle has the larger diameter: the one with the same area as the area of the Czech Republic, or the one with a circumference equal to the length of the border of the Czech Republic? Then check your guess by calculating. The area of the - Bar
Half of the bar is green, the third is yellow, and the remaining 40cm is red. How long is a bar? - Garden on map
On a map with a scale of 1:5000, the grandfather's garden is represented by a rectangle measuring 4 cm and 3 cm. What dimensions will it have on a map scale of 1:4000? - Number calculation
Find a number from which 5% is as many as 7% out of 45. - Scout trip
During the trip, the scouts ran 1/2 of the route on the first day, 2/5 of the route on the second day, and on the third day, they were still 12 km away. How many km have they traveled in all three days? - Pool water
The block-shaped pool is 8.5 m long, 4.3 m wide, and 1.5 m deep. How many hectoliters of water is in it when it is filled to three-fifths of the depth? - Expression substitution
Determine the value of the expression by substituting for the variables a = 5, b = 2, x = 3, y = 1: k = 4ab + 1/2 ab - 14 l = x² + 2xy + y² m = 5b³ - 4b² - Measuring cork
Simon boasted that he had taken away a block of cork measuring 0.5 m x 0.5 m x 1.2 m. Is it possible we know that 1 m of cubic cork weighs 300 kg and children from 10 to 15 years old can carry a maximum load of 5 kg? - Surface of a cube
The cube's edge, the volume of which is 58.3% of its surface, is: a) 3.5cm b) 4.5cm c) 2.5cm d) 1.5cm - Ghost clock
At 6:15, a ghost conjured a clock that showed the correct time. At that moment, the hands on the clock began to move at the correct speed but in the opposite direction. The ghost reappeared at 7:30 p.m. What time was the clock showing at this moment? - Tank
1080 hectoliters of water were flowed into a cuboid tank whose bottom dimensions are 9 m and 15 m. This filled 40% of the tank's volume. Calculate the tank's depth. - Tank cans
The garden tank is filled to the brim with water. The bottom of the tank is a rectangle with sides of 150 cm and 160 cm, and the height of the tank is 0.8 m. How many 15 l cans can we use to empty the garden tank? - The cube
The cube has a surface area of 486 m². Calculate its volume. - Joining 3 cubes
We place three identical cubes with an edge length of 3 cm on top of each other. What is the surface of the resulting block? - Percentage calculation
What percentage are 720 liters of 6m³?
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