Maths practice for 12-year-olds - page 191 of 347
Number of problems found: 6923
- Reservoir - spherical
The reservoir is a sphere with a diameter of 12 m. If it is painted twice, how many kg of paint is needed to paint it, and one kilogram is enough to paint about 8 m²? - Triangle revolution volume
What is the hole volume drilled by the drill in the shape of a right triangle that revolves around a longer perpendicular? The perpendiculars of the triangle are 10 cm and 3 cm long. - Pocket money savings
Zuzana receives pocket money from her parents. In October and November, she managed to save 288 euros. The ratio of money saved for October and November is 5:4. How many euros did Zuzana save in October, and how much in November? - Diamond circumference calculation
In the diamond ABCD, the angle BAD is 60°; the length of the diagonal BD is 7 cm. Calculate the circumference of the diamond. - Cube weight comparison
The cube weighs 32 kg. How much kg does a cube made of the same material, which has an edge four times shorter, weigh? - Block dimension ratio
The block's dimensions are in the ratio 16:12:8, and the sum of these dimensions is 240 decimetres. What are the dimensions of the block? - Math grade distribution
From the quarterly work in mathematics in the eighth grades, 1/3 of all pupils got a one, 2/7 of all pupils got a two, 5/8 of the rest got a three, 8 pupils got a four, and 4 got a five. How many students wrote a paper? How many got a one, a two, and how - Box paper calculation
How many m² of paper are needed to produce 1000 pieces of cube-shaped boxes with an 8 cm edge when we must add one-quarter of the area to the joints? - Seed drill area
The diameter of the seed drill wheel is 90 cm, and the working width is 240 cm. Calculate the field area if the wheel turns 200x. - Gasoline oil mixture
Gasoline will be mixed with oil. The recommended mixing ratio of oil and petrol is 1:50. We have 5 liters of gasoline in the canister. How many deciliters (dl) of oil must add to keep the recommended ratio? - Room brick calculation
Calculate how many bricks we will need to build a room that should be 1.8 m wide, 2 m long, and 2.4 m high. The dimensions of the brick are 25 cm x 60 cm. - Tractor wheel turns
The large wheel of the tractor has a diameter of 1.20 m. The small wheel has a radius of 35 cm. How many turns will a small bike make on a 5 km long track? - Liquid
How much liquid does the rotary cylinder tank hold with a base diameter of 1.2m and height of 1.5m? - LCM GCD division
What result do we get when dividing the least common multiple of the numbers 12 and 8 by their greatest common divisors? - Highway calculation
How many meters does a car travel on the highway at a speed of 130 km/h per second (use a simple proportion)? - Lunch
Lunch is given to seniors from 12:15 to 12:40 during the Coronavirus pandemic. What angle will the minute hand of the clock describe during this time? - Stream cleanup calculation
The scouts decided to clean up the stream outside the town. On the first day, they cleared half of the total length of the stream. On the second day, 2/7 of the entire length. On the third day, they cleared a third of what was left, and on the fourth day, - Grandma
6 kg of potatoes is enough for four people at home for 15 days. If Grandma visits, how many days will this amount be enough? - Triangle side length
The sizes of the sides of a triangle are three natural numbers. The two shorter sides have lengths a = 7 cm and b = 9 cm. What size will the third side be if we want the triangle to have the largest possible perimeter? - Pancake baking calculation
Mom baked pancakes and put them on a plate. After Mike had eaten three-sevenths of them, his brother Pete came and took three-quarters of the pancakes from the plate. In the end, Jane finished the remaining 7 pancakes. How many pancakes did mom bake?
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