Mathematical Operations and Problem Solving

The video tutorial covers a series of math problems from the OSN 2023 competition for elementary students. It begins with an introduction and proceeds to solve various problems involving percentages, operations with numbers, subtraction, averages, combinatorics, factors, multiples, geometry, ratios, distance, speed, and route finding. Each problem is explained step-by-step, providing a clear understanding of the concepts and methods used to arrive at the solutions.

What is the result of the operation involving 125% of a number, fractions, and division?

• 0.5

• 1

• 2

• 3

If m and n are two distinct natural numbers, which operation result is correct?

• 19

• 17

• 47

• 39

In a subtraction operation, if the result is 4, what is the value of the triangle symbol?

• 10

• 8

• 7

• 9

How do you calculate the average number of voters excluding heads of families?

• Divide total voters by 4

• Add heads of families to total voters and divide by 4

• Multiply total voters by 4

• Subtract heads of families from total voters and divide by 4

How many ways can Felyi choose 3 books and 2 pens from different brands?

• 250

• 210

• 120

• 150

What is the greatest common divisor of 3 and a number a, if it is given as 3?

• 3

• 1

• 5

• 7

If the least common multiple of 15 and a number a is 105, what is the value of a?

• 15

• 21

• 35

• 45

What is the ratio of the shaded area to the unshaded area in the given circle problem?

• 1:1

• 2:1

• 3:1

• 4:1

How far does Butet travel if she walks for 45 minutes at 4 km/h and runs for 30 minutes at 10 km/h?

• 5 km

• 6 km

• 8 km

• 7 km

If the third quarter sales are 20% of the total annual sales, what is the fourth quarter sales?

• 4.5 tons

• 5 tons

• 6.5 tons

• 7 tons