Maths practice for 12-year-olds - page 90 of 355

Number of problems found: 7086

Jabu had
Jabu had a few marbles. Today, he played and doubled his number. Then Thabo gave him three marbles for free. Jabu now has 21 marbles. How many did he have before he started playing? Solve this problem using a suitable model.
Number difference integer
The difference between two positive integers is 25. One number is 59. What is the other number?
Double of one-third
¹/₃ of the school garden has vegetables, and another ¹/₃ has flowers. What part of the garden is left to grow grass?
Yesterday 6
Yesterday it was 24°C, and today it is 28°C. By how many degrees has the temperature increased?
There 22
There is 5/8 of a pizza in one box and 9/12 of a pizza in another box. How much do you have altogether?
Work space
Every person in a conference room must have at least 36 square feet of workspace. A conference room is 28 by 20 ft. find the maximum number of people the room can accommodate.
Johnny 2
Johnny spends 1/2 of his salary on his family, 1/6 on personal expenses, and 1/9 on convenience, and he saves the rest. What fraction of his salary does he have? How much money does he save from his salary of $180?
Sphere diameter
The sphere has a diameter of 70 cm. Calculate its surface area and volume.
Sophomores
There are 3200 students at Lake High School, and 3/8 of these are sophomores. If 3/5 of the sophomores favor the school forming a crew team and 7/10 of the remaining students (not sophomores) are in favor of forming a crew team, how many students are oppo
The temperature 34
The temperature on a maths exam day went down 2°C and then 3°C ending up as a final temperature of 27°C. What was starting temperature?
Number divisibility nine
What digit should X replace so that the number 6X94 is divisible by nine?
ABC gifts
Arthur had 30 dollars to spend on three gifts. He spent 9 3/4 dollars on gift A and 4 1/2 dollars on gift B. How much money did he have left for gift C?
Cone volume surface
Calculate the volume and surface area of the cone with a diameter of 20 cm and a height of 15 cm.
Number ratio division
Divide the number 34 in the ratio of 3:4:10.
Three-digit number creation
From the number 5,4,0,7,8, create three-digit numbers, so they do not repeat and solve the problem by calculation.
Car's mileage
A car owner has her tank filled and notices that the odometer reads 14,368.7 kilometers. After a trip in the country, it takes 34.5 liters to fill the tank, and the odometer reads 14,651.6. How many kilometers per liter is this car getting?
Triangle perpendicular perimeter
The perimeter of a right triangle is equal to 30 centimeters. Calculate the perpendicular b if a = 5 centimeters and c = 13 centimeters. A natural number expresses the length of the perpendicular b.
Centi-year deca-month comparison
How many minutes is the centi-year longer / shorter than a deca-month? The year is 365 days, and the month is 30 days.
Two boxes 2
The students filled two boxes with 5-peso coins. Box A has 300 5-peso coins, and Box B has 450 coins. In what way is the volume of box A lesser or smaller than the volume of box B? Explain your answer.
Wooden prism
The wooden prism weighs 5 kg and has a 700 kg/m³ density. Calculate the volume of the wooden prism.

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