Maths practice for 12-year-olds - page 188 of 347

Number of problems found: 6923

Tank solution fitting
Will 600 liters of solution fit in a cuboid-shaped tank with bottom dimensions of 2.5m and 1m and a height of 3dm?
Resistor voltage calculation
The resistor has a value of 50 ohms, and a current of 120 mA passes through it. What is the voltage across the resistor?
Channel cross-section area
Calculate the cross-sectional area of the trapezoidal channel irrigation channel if its upper width is 7.9 m, its bottom width is 5.5 m, and its depth is 2.8 m.
Sticker paper calculation
The sticker is shaped like a triangle with a side 5.4 cm long and 3 cm high. Most of such stickers can be made of 1 m² paper.
A lot of hay
Martin's grandfather weighed a lot of hay and calculated that it would last 100 days for 15 rabbits. How many days will this lot be enough for 25 rabbits?
Snack
The teacher paid CZK 450 for a snack for 30 pupils. How many CZK will we pay for the same snack for 28 pupils?
Granite cube buoyancy
The granite cube with an edge length of 1 dm and a weight of 2.5 kg is immersed in a container with water. How much buoyancy makes it lighter? How much compressive force does the cube exert on the bottom of the container?
Rectangle area comparison
The rectangle has 10 and 8 cm dimensions on a 1:10 scale plan. How many times does it have more area than on the plan?
Corridor plastering time
According to the standard, we calculated that two masons would plaster the corridor of the new school building in 54 hours. How long would it take for nine bricklayers to plaster this corridor?
Coal supply duration
With the consumption of 0.4 t of coal per day, the supply lasts for 36 days. How many days will the supply be enough if 16 kg of coal is used less daily?
Apple drying calculation
Last year, Mirek's aunt dried 4.8 kg of fallen apples from 30 kilograms of fallen apples. He wants to dry the crosses from 50 kilograms of apples this year. Approximately how many kg will he gain?
An example
An example is playfully for grade 6 from Math, and I don't know how to explain it to my daughter when I don't want to use the calculator to calculate the cube root. Thus: The student made a cuboid from a block of 16x18x48 mm of plasticine. What will be th
Harvester wheat calculation
A field of wheat can be harvested by 7 combine harvesters in 5 days at full capacity. The weather forecast called for the harvest to be completed in 4 days. How many combines were needed in total?
Class girl calculation
One-fifth of the girls are honored in the class, and the remaining eight girls are doing well. How many girls are in the class?
Triangle branch length
The right triangle has an area of 225 cm². One of its legs is twice the length of the other. Find the lengths of its legs.
Reducing
Reducing the unknown number by 427, we get 65% of its value. What is an unknown number?
Class student formula
There are x girls and nine boys in the class. Write a formula for the number y of all students in the class. Express the number of girls from the formula.
Two rectangular boxes
Two rectangular boxes with dimensions of 5 cm, 8 cm, 10 cm, and second of 5 cm, 12 cm, and 1 dm will be replaced by a single cube box of the same cubic volume. Calculate its surface.
Ant food transport
Fifteen ants bring 10 g of food to the anthill in 1 hour. In how many hours will five ants carry 1 kg of food?
The largest
We cut the largest possible cylinder from a 20 cm cube. What is the volume of this cylinder?

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