Problem Description:
The task is to identify and circle all the
prime numbers from the given list of numbers. A prime number is defined as a number greater than 1 that is divisible only by itself and 1. The numbers 0 and 1 are neither prime nor composite.
Given Numbers:
The numbers are arranged in a grid format:
```
70, 65, 25, 16, 90
55, 61, 80, 77, 32
42, 60, 93, 29, 79
56, 54, 24, 18, 96
71, 26, 68, 20, 85
58, 30, 76, 46, 31
```
Solution Approach:
1.
Definition Recap: A prime number is greater than 1 and has no divisors other than 1 and itself.
2.
Check Each Number: For each number in the list, determine if it is divisible by any number other than 1 and itself. If it is, then it is not a prime number.
3.
Eliminate Non-Prime Numbers: Numbers that are divisible by any other number (besides 1 and themselves) are not prime.
4.
Identify Prime Numbers: Circle or mark the numbers that satisfy the prime number condition.
Step-by-Step Analysis:
#### Row 1:
-
70: Divisible by 2, 5, 7, 10, etc. →
Not Prime
-
65: Divisible by 5, 13 →
Not Prime
-
25: Divisible by 5 →
Not Prime
-
16: Divisible by 2, 4, 8 →
Not Prime
-
90: Divisible by 2, 3, 5, 6, 9, 10, etc. →
Not Prime
#### Row 2:
-
55: Divisible by 5, 11 →
Not Prime
-
61: Only divisible by 1 and 61 →
Prime
-
80: Divisible by 2, 4, 5, 8, 10, etc. →
Not Prime
-
77: Divisible by 7, 11 →
Not Prime
-
32: Divisible by 2, 4, 8, 16 →
Not Prime
#### Row 3:
-
42: Divisible by 2, 3, 6, 7, 14 →
Not Prime
-
60: Divisible by 2, 3, 4, 5, 6, 10, 12, etc. →
Not Prime
-
93: Divisible by 3, 31 →
Not Prime
-
29: Only divisible by 1 and 29 →
Prime
-
79: Only divisible by 1 and 79 →
Prime
#### Row 4:
-
56: Divisible by 2, 4, 7, 8, 14 →
Not Prime
-
54: Divisible by 2, 3, 6, 9, 18 →
Not Prime
-
24: Divisible by 2, 3, 4, 6, 8, 12 →
Not Prime
-
18: Divisible by 2, 3, 6, 9 →
Not Prime
-
96: Divisible by 2, 3, 4, 6, 8, 12, 16, 24, 32, 48 →
Not Prime
#### Row 5:
-
71: Only divisible by 1 and 71 →
Prime
-
26: Divisible by 2, 13 →
Not Prime
-
68: Divisible by 2, 4, 17 →
Not Prime
-
20: Divisible by 2, 4, 5, 10 →
Not Prime
-
85: Divisible by 5, 17 →
Not Prime
#### Row 6:
-
58: Divisible by 2, 29 →
Not Prime
-
30: Divisible by 2, 3, 5, 6, 10, 15 →
Not Prime
-
76: Divisible by 2, 4, 19 →
Not Prime
-
46: Divisible by 2, 23 →
Not Prime
-
31: Only divisible by 1 and 31 →
Prime
Final List of Prime Numbers:
From the analysis, the prime numbers in the list are:
- 61
- 29
- 79
- 71
- 31
Circled Answer:
The circled prime numbers in the grid would be:
```
70, 65, 25, 16, 90
55, 🟩61, 80, 77, 32
42, 60, 93, 🟩29, 🟩79
56, 54, 24, 18, 96
🟩71, 26, 68, 20, 85
58, 30, 76, 46, 🟩31
```
Final Answer:
\boxed{61, 29, 79, 71, 31}
Parent Tip: Review the logic above to help your child master the concept of prime number worksheet 4th grade.