Math practice for 13 year olds - page 160 of 428
Number of problems found: 8558
- Natural number creation
How many natural numbers can you make from the digits contained in the number 4002? No digit may be repeated in the number entry. However, not all digits must be used. Sort the numbers in ascending order of size. - Mushrooms
Mr. Mushar collected mushrooms. One-fifth he gave to neighbors, one-third to dry, and divided the remaining mushrooms into three equal parts: himself, son, and daughter. Daughter Dominika got 42. How many mushrooms did he collect in total, and how many mu - Two-digit number In a two-digit number, the number of tens is three greater than the number of units. If we multiply the original number by a number written in the same digits but in reverse order, we get product 3 478. Find the original number.
- Book reading ways
Martina borrowed three novels and two travelogues from the library. He will read the travelogues first. How many ways can he read the books? - Top-open tank
The top-open tank resembles a truncated rotating cone, standing on a smaller base. Its volume is 465 m3, and the bases' radii are 4 m and 3 m. Find the tank's depth. - The truncated
The truncated rotating cone has bases with radii r1 = 8 cm, r2 = 4 cm, and height v = 5 cm. What is the volume of the cone from which the truncated cone originated? - We roll
We roll two dice A. - what is the probability that the sum of the falling numbers is at most 4 B. - is at least 10 C. - is divisible by 5? - Square root
Calculate the product of the sum and difference of the numbers of the square root of 5 and the square root of 3 (in this order). - Triangle angle ratio
The sizes of the interior angles of the triangle are in a successive ratio of 6:4:5 are these angles big? - Swimming student
There are 200 pupils in the class, 40% of whom cannot swim. How many students can swim? - Workshops
The plant has three workshops. In the first workshop, produce five products/hour. In the second 8 products/hour, and in the third, seven products/hour. In the first workshop, they produced 240 products. In the second 400 and the third 350 products. Find t - Czech coins
John has 540 CZK, but he only has 10 and 20 CZK coins. We know that he has 10 CZK coins, seven times more than 20 CZK coins. How many 10CZK coins and how many 20CZK coins did he save? - Flower box
A wooden flower box in the shape of a cuboid has the following external dimensions: length 120 cm, width 15 cm, and height 20 cm. It is made of wooden slats 1.5 cm thick. a) At least how many m² of slats were needed to make it? Calculate according to the - A wheat
A wheat factory packages wheat in sacks of three different colors. The following table shows the amount of wheat (in kg) packed in each type of sack. White sack 2 kg Brown sack 3 kg Black sack 4 kg What is the total amount of wheat (in kg) which can be pa - Quadrilateral sides
What is the perimeter of a quadrilateral whose first side is 3 cm longer than the second side, the third side is 5 cm shorter than the fourth side, and the second side is 2 cm shorter than the fourth side? - Car sign
How many cars can we mark with signs that only use the letters A, B, and the number 1,2? The tag contains two letters and three digits. - Pyramid stone weight
The largest Egyptian pyramid has the shape of a regular four-sided pyramid with a base edge of approximately 227 meters and a height of about 140 meters. How many tons of stone did the workers transport to build it? One cube of stone weighs 2500 kg and ne - The golf
The golf ball with a diameter of 43 mm is packed in a cube-shaped box. What percentage of the box volume is made up of a ball? - Plot dimension increase
The surface area of the rectangular plot needs to be increased by 33.7 percent. One dimension was extended by 2.9 percent. By what percentage should the second dimension be increased? Round the result to two decimal places. - Fireplace power consumption
A current of 20 A passes through the heating spiral of the electric fireplace with a resistance of 10Ω for 2.5 hours. Determine the power input of the fireplace and the consumed electrical energy
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