Maths practice for 12-year-olds - page 283 of 359

Number of problems found: 7167

Square diagonal
Determine the diagonal of a square whose perimeter is equal to 72 cm.
Expression evaluation
For the variables x = -8, y = 12, z = -5, evaluate these two mathematical expressions a = y-z b = z / (x-z)
Average speed
At what average speed would you have to travel around the world in 80 days? (Assume a path along the equator; round to km/h.)
Square diagonal
Calculate the diagonal of a square whose area equals 625 square centimeters.
Expression evaluation
For the variables x = 8, y = 12, z = -5, evaluate these two mathematical expressions a = y-z b = z / (x-z)
Cube measurements
The surface area of one cube wall is 2500 square millimeters. Determine the cube's surface, the length of its edge, and its volume.
Cube 5
The surface area of one cube wall is 32 square centimeters. Determine the length of its edges, its surface, and volume.
Cube edge
Determine the edge length of a cube whose surface area is 37.5 cm².
Unknown number 7
16% of the unknown number is 21 less than the unknown number itself. Determine the unknown natural number.
Three children
Three children eat 8 chocolates in 6 days. How many chocolates do 6 children eat in 18 days?
Coconut percentage
The bar contains 81g of coconut per 200g. What percentage of coconut does the bar have?
Cocoa percentage
Chocolate has 86% cocoa. Determine how many grams of cocoa are in 165-gram chocolate.
Square root sum
Determine the sum of the square roots of 81.
Root calculation
What is equal to twice the sixth root of 729?
Percentage calculation
Determine how much equals 16% of a) 32, b) 44, c) 34, d) 25
Change the numbers in the ratio
Change the numbers 29, 38, and 43 in a 3:4 ratio.
Runner 2
Marian runs 12 meters in 8 seconds. How far would Marian run for 70 seconds if he still runs at the same pace?
Work time
Josef would do the work himself in 5 hours. Josef and Michael would do the work together in 3.5 hours. Determine how long it would take Michael to do the job independently.
Task completion
Milos had to do 20 clicks. However, he only made 16. What percentage did he miss in completing the task?
Unknown number 5
Daniel thinks of an integer. When he changed this number to a ratio of 2:5, he got the number 2.8. Determine what number Daniel thinks.

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