Maths practice for 12-year-olds - page 45 of 351

Number of problems found: 7020

Average 110
The average of five numbers is 1.3 their sum is? The arithmetic mean of the numbers 0.04; 0.014; 0.21 is? The arithmetic mean of four decimal numbers is 2.5. Three of these numbers are 1.8; 0.65; 3.1 the fourth number is?
Two cuboids
The cuboid has dimensions of 2m 3m 4m We increase the length of all edges by 50 cm. 1. Calculate in % how much the surface area of the cuboid increases compared to the surface area of the original cuboid - round the result to whole percent 2. Calculat
Buses 7
Two lines leave the bus stop according to the schedule A) 8:00 every 6 minutes until 23:00h B) 8:00 every 14 minutes until 23:00h How many times will buses of both lines leave the bus stop simultaneously between 8:01 and 20:00?
Heating water
5 kg of water warmed up by 10°C. How much heat did the water absorb? (Remember that 1kg of water needs 4,200J of heat to raise its temperature by 1°C.)
Kilograms 84201
60 kg of fruit were divided into the KOP store and the FRESH store in a ratio of 2:3. How many kilograms did the FRESH store receive?
Received 84200
Jana received a new book. She wants to read it in 8 days. If she read 6 more pages a day, she would read the book two days earlier. How many pages does the book have?
Multiplying 84192
What do we get by multiplying the absolute value by the number -0.7 and the reciprocal of the number by the number 10?
Raspberry juice
How much will the scout leader pay for drinks for the children if a third of the children had a raspberry juice for 10 CZK, half of the children had sparkling water for 15 CZK, and the remaining 4 children had a kola for 20 CZK (CZK = Czech crowns)?
Dependent variables
A printer prints k sheets in n seconds ( k, n ϵ N ). Express the number of sheets that the printer prints in 5 minutes in terms of k and n.
Concert organizers
800 people came to the concert, a quarter more than the organizers expected. How many people did the organizers expect?
Quarter 84177
We used one-quarter of the coal we bought, leaving us with 12 q. How much coal did we buy?
Cutting a cuboid
A cuboid can be cut into 200 cubes, each with a volume of 8 dm cubic. Calculate how many cubes with a volume of 1 cm cubic can this cuboid be cut into without a remainder.
Arithmetic 84171
The arithmetic mean of two numbers is 10. One of the numbers is 2. What is the second number?
TEV physical education
The students lined up in threes in a physical education class, then in fours, and there was always one extra student. What is the least number of students that could be in the gym?
Boxes of wafers
Wafers measuring 11 3/4 cm, 4 2/5 cm, and 1 2/3 cm are packed in rectangular boxes measuring 23 1/2 cm, 26 2/5 cm, and 6 2/3 cm. What part of the volume of the box does one wafer make up?
MO Z7 2025
Adela and Susan ate plums. On the first day, Adela ate three quarters of what Susan ate that day. On the second day, Susan ate three halves of what Adela ate that day. Together, they ate 31 plums over the two days, and each girl ate the entire number of p
Create 2
Create a suitable table and fill in the data: The production of four machines takes a total of 80 hours. Each machine is produced for the same amount of time. How long does it take to produce 1 machine, 2 machines, 5 machines?
From tank 2
First 1/3 was drained from the water tank, then 1/4. There were 20 liters of water left in the tank. How many liters of water were in the tank at the beginning?
Peter 27
Peter earned twice as much as Jano on his part-time job. Jano earned 50 euros less than Peter. How much did each of them earn?
Irregular
Calculate the area and perimeter of the garden that was created from a rectangular plot measuring 10 by 20 meters after transferring one corner measuring 6 by 7 meters. The separated rectangular plot has parallel sides to the main plot. Did the perimeter

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