Ivan added all even two-digit numbers smaller than 17, and Peter added all odd two-digit numbers smaller than 16. By how much is Ivan’s sum greater than Peter’s sum?

How many numbers are missing from the following number sequence?

7, 14, 21, ..., 63, 70, 77

Which one-digit number has the greatest sum of its factors?

How many tens does the number equal to

222 – 23 + 223 – 24 + 224 – 25 + 3 have?

A sports club has more than 24 children who are members. The number of girls is twice that of the boys. At least how many members does this club have?

I

know 29 children who were born in the same month. How many of these children

were definitely born on the same day of the week?

How can we get the number 100 by using five digits 1 and some arithmetic symbols? Write down your answer in the answer sheet.

We have 3 keys and 3 briefcases. At least how many attempts should we make in order to match each key to each briefcase? (It is not necessary to open the briefcases)

A mother invited all 3 of her daughters and all of their children to her house. Each of her daughters has exactly 3 children. How many people were there in the house in total?

An isosceles triangle has a perimeter of 50 cm. The length of one of its equal sides is 2 dm. Find the length of its different side in centimetres.

The perimeter of a square is 36 cm. The side length of a rectangle is equal to the side length of the square, and the width of the rectangle is 1 cm shorter than its length. Find the perimeter of the rectangle in centimeters.

Find the smallest number of straight lines that would be necessary in order to form 3 rectangles?

Four different points - А, В, С and D have been placed along the same straight line, and are such that АВ = 7 cm, АD = 4 cm, АС = 4 cm. What is the distance between the points В and D in centimetres?

A rectangle with a perimeter of 48 cm has been divided into 5 identical squares. Find the perimeter of the square in centimetres.

For how many three-digit numbers is the following statement true?

“After erasing the ones digit, we get a number smaller than 15.”

How many two-digit numbers are divisible by 3, but are not divisible by 6?

Ivan has seven $1 coins, two $2 coins and two $5 coins. In how many ways can he pay for a book that costs $10 without having to get change?

How

many three-digit numbers have 6 as the product of their digits?

At least how many of the integers 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 should we choose randomly so that at least 2 among them would have a sum of 14?