Maths practice for 12-year-olds - page 210 of 355

Number of problems found: 7083

Thought number puzzle
When I add half of the thought number to 3/5 of the thought number, I get the sum of 22. Which number do I think?
Expression equality puzzle
For what values of x is the value of the expression 5x + 11 equal to that of the expression 7x + 31?
Expression value puzzle
Find for which x the value of the expression 13x - 7 is eight less than the value of the expression. 12x + 11.
Natural number sum
The sum of three natural numbers is 204. Each of them is five greater than the previous one. What are the numbers?
Column height puzzle
The height of the column is 75 cm and still half its height. How tall is the pillar?
Dentist
Class 5. I participated in a preventive dental examination. A quarter of the pupils found two dental caries, and an eighth found one caries. Half the class had all their teeth healthy. How many students attend class 5? If four students were missing on the
Rectangle side measurement
One side of the rectangle is 8 cm long. When we enlarge the dimensions of this rectangle four times, we get a rectangle with a circumference of exactly 1m. How many mm does the other side of the unmagnified rectangle measure?
Six percents
6% of the base is 21. How much is 28% of this base?
Initial price
The price of the T-shirt was initially 379 CZK, but it was reduced by 16%. How much does it cost now?
Candy color ratio
The number of blue and green candies is 5:6. and The number of red and green candies is 3:8. Determine the ratio of red and blue candies.
Finding Unknown Number
By reducing the unknown number by 342, you get 81% of the unknown number. Find this number.
Prize Sharing Ratio Total
Matej, Simon, and Peter shared a profit in the ratio of 3:4:5. How much did they win in total if Matej received CZK 1,520?
The sponsor
The school received money from the sponsor. She used one-third to buy computers and half of the rest to adjust the gym. It still has 4000 euros left. How many euros did the sponsor donate to the school?
Prism 4 sides
Find the surface area and volume of a four-sided prism high 10 cm if its base is a rectangle measuring 8 cm and 1.2 dm.
Brick density calculation
Jeníček weighed a broken piece of brick and found that it weighed 48 grams. Using a measuring cylinder, he determined its volume at 30 cm³. What is the density of the brick?
Lumberjacks Trees Three Days
Lumberjacks cut down a predetermined number of trees over the course of three days. On the first day, they cut down a quarter of the trees; on the second day, they cut down 6 more trees than on the first day; on the third day, they cut down 6 more trees t
Pool tiling
The first tiler would cover the inside of the pool in 5 working days, and the second would need seven working days for the same work. In how many days would they line the inside of the pool together?
Reading Book Pages Schedule
Roza calculated that if she read ten pages a day, she would read the whole book in 18 days. After a week, however, she decided to read one more page a day. How many days will he read the entire book?
Diameter of cent coins
In what proportion are the diameters of these coins: 10 cents-diameter 19.75mm 20 cents-diameter 22.25mm 50 cents-diameter 24.25mm
Step count
George makes steps 60 cm long. He will take 1530 steps on the way to school. How many steps will his father take to the class meeting if he makes steps 85 cm long?

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