The problem has two parts. Part 1: We need to choose three numbers from the given set {3, 8, 9, 1} to form a three-digit even number that is greater than 400. Part 2: We need to find the missing numbers in two equations: 55 + ? = 120 600 x 4 = ?

1. Problem Description

The problem has two parts.

Part 1: We need to choose three numbers from the given set {3, 8, 9, 1} to form a three-digit even number that is greater than

4

0

0. Part 2: We need to find the missing numbers in two equations:

55 + ? = 120

600 x 4 = ?

2. Solution Steps

Part 1:

To form an even number, the last digit must be even. From the given numbers, only 8 can be in the units place. So the number has to end with

8. The number has to be greater than

4

0

0. So the first digit can be either 9 or

3. The options with the numbers are 9 _ 8 or 3 _

8. If we use 9 as the hundreds digit, the second digit can be 1 or

3. We choose 9, 1, 8 to get the number

9

1

8. We choose 9, 3, 8 to get the number

9

3

8. Both are greater than 400 and are even numbers.

If we use 3 as the hundreds digit, then the other two numbers must be 9 and

8. Therefore the three-digit number must be 398, which is less than 400, so it cannot be used. Thus, we choose the numbers 9, 1, and

8. Since the number must be even and greater than 400, we arrange them to make

9

1

8.

Part 2:

For the first equation, 55 + ? = 120, we need to find the difference between 120 and

5

5. ? = 120 - 55

? = 65

For the second equation, 600 x 4 = ?, we need to find the product of 600 and

4. ? = 600 x 4

? = 2400

3. Final Answer

Part 1: 918

Part 2: 65, 2400