Math Olympiad 4

Number Sense ( Week 16 Evaluation)

1. What is the natural number comes exactly in the middle between 4 and 8?

2. 433 is a 3-digit number with each digit less than or equal to the digits in higher place values, i.e 3 ≤ 4 and 3 ≤ 3. How many such 3-digit number(s) are there between 150 and 199 inclusively?

3. If the odometer of a car reads 41,269 miles, what is the next odometer reading with at least four digits that are the same?

4. What is the greatest common factor (GCF) of 35 and 27?

5. In the product 10 × 11 × 12 × 13 × 14 × 15 × 16, which one of the seven numbers should be reduced by 1 to cause the smallest decrease in the product?

6. In the number sequence below, there is a number which is special. What is it?
12, 18, 24, 30, 36, 38.

7. What positive integers are equal to their rightest digit squared?

8. Using all the numbers of 4, 6, 7, 8, 10 and +, +, −, × operators, can an even number and an odd number be produced respectfully?

Yes No

9. Which of the following statements is correct?

A) To subtract an integer is the same as to substract the opposite of the integer

B) To add a positive integer is the same as to subtract an negative integer

C) The sum of two integers is always larger than difference of the two integers

D) The sum of an integer and its opposite is zero

10. Make a 5 using the following 5 numbers: 3, 4, 5, 5 and 4. You can use +,-,*,/, and ( ) as many times as you wish, but you need to use all 5 numbers and each number only once.