Math practice for 13 year olds - page 374 of 423
Number of problems found: 8445
- Rectangle - parallelogram
A rectangle is circumscribed by a circle with a radius of 5 cm. The short side of the rectangle measures 6 cm. Calculate the perimeter of a parallelogram ABCD, whose vertices are the midpoints of the sides of the rectangle. - TVs
Production of television sets increased from 3,500 units to 4,200 units. Calculate the percentage of production increase. - Sweets
Three chocolates and seven cakes cost 85 CZK. Two chocolates and six cakes cost 86 CZK. How much are five chocolates and nine cakes? I wonder how to get the result, but only by logic, without using a system of equations. - Cube 5
The surface of the cube is 15.36 dm². How will this cube's surface area change if the edges' length is reduced by 2 cm? - Regular octagon
Draw the regular octagon ABCDEFGH inscribed with the circle k (S; r = 2.5 cm). Select point S' so that |SS'| = 4.5 cm. Draw S (S'): ABCDEFGH - A'B'C'D'E'F'G'H'. - Metal sheet
The box has the shape of a cube with an edge length of 50 cm. How much m² of sheet metal is needed to beat a box if we add 20% on the folds of the lid and walls? - Bricks
Openings in perforated bricks occupy 10%, and brick has dimensions of 30 cm, 15 cm, and 7.5 cm. Calculate a) the weight of a perforated brick if you know that the density of the full brick material is p = 1800 kg/m³ (1.8 kg/dm³) b) the number of perforate - Nectar
Nectar collected by bees contains 70% water. The nectar of the same process produces honey which has 19% water. How many kilograms of nectar do bees need to collect to make 1 kg of honey? - Workers
Ten workers must pave the road for 22 working days. After four days were spent speeding up work, two more workers were added. a) After how many work days do workers complete the paved road? b) How many working days does a total paved road take? - Apprentice
The worker and apprentice execute the work for 6 hours. The worker performs himself in 10 hours. How long does the work of an apprentice take? - Shepherd
The shepherd has fewer than 500 sheep; where there can be up to 2, 3, 4, 5, or 6 rows, there is always one remaining, and it can be increased up to 7 rows of sheep, and it is not increased any ovine. How many sheep have a shepherd? - Plum
On the platter are plums. How many were there if its have to be able to share equally among 8,10, and 12 children? - Square grid
A square grid consists of a square with sides of a length of 1 cm. Draw at least three patterns, each with an area of 6 cm² and a circumference of 12 cm, and their sides in a square grid. - Cuboid box
How much m² paper is needed for the sticking cuboid box of dimensions 50 cm, 40 cm, and 30 cm? To the folds, add one-tenth the area. - Container with water
The weight of a container with water is 2.48 kg. Suppose the cast is 75% water, and the container with water weighs 0.98 kg. Determine the weight of the empty container. How much water was originally in the container? - Lift
The largest angle at which the lift rises is 16°31'. Give climb angle in permille. - Sheep
Shepherd is tending the sheep. Tourists asked him how much they had. The shepherd said, "there are fewer than 500. If I lined up in 4-row, three remain. If in 5-row, four remain. If in 6-row, five remain. But I can form 7-row." How many sheep have a sheph - Three friends
Petra was ill with three friends, each on a different day. Find out which day, who came, and what they handled. They came in three consecutive days a week. The first came on Tuesday. Karol did not come on Tuesday. Mirko arranged to change the date of the - Gearing
Gearing consists of two wheels. One is 88, and the second is 56 teeth. How many times turn the smaller wheel to hit the same teeth as in the beginning? How many times will we turn the biggest wheel? - Tissues
The store got three kinds of tissues - 132 children, 156 women, and 204 men. Tissues for each species were packed into boxes after the number of pieces was the same for all three types (and greatest). Determine the number if you know that every box has mo
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