To solve this problem, we need to identify all the prime numbers in the grid from 1 to 100.
Step 1: Understand Prime Numbers
A prime number is a whole number greater than 1 that has only two factors: 1 and itself. This means it cannot be divided evenly by any other number.
- The number 1 is
not prime.
- Even numbers greater than 2 are
not prime (because they can be divided by 2).
- Numbers ending in 5 (greater than 5) are
not prime (because they can be divided by 5).
Step 2: Check the Numbers Row by Row
Let's go through the grid and pick out the primes. The image already shows some highlighted in pink, so we will verify those and find any missing ones or confirm the full list.
*
Row 1: 2, 13, 47 are prime. (16, 21, 50, 74, 80, 36, 64 are not).
*
Row 2: 57 is divisible by 3 ($5+7=12$), so it's not prime. 89, 3, 29, 43 are prime. (1, 8, 92, 58, 85 are not). *Note: The image highlights 57 incorrectly as pink, but 57 is $3 \times 19$. However, looking closely at the provided "Answer Key" image, 57 is NOT highlighted pink. Wait, let me re-examine the image carefully.*
* Looking at Row 2: `1`, `57`, `89`(pink), `3`(pink), `29`(pink), `43`(pink), `8`, `92`, `58`, `85`.
* Correct primes here: 89, 3, 29, 43.
*
Row 3: 28, 45, 75, 62, 34 are not prime. 5, 23 are prime. 40, 12, 27 are not prime.
*
Row 4: 65 (ends in 5), 77 ($7 \times 11$), 51 ($3 \times 17$), 84, 4, 30, 97(prime), 31(prime), 37(prime).
* Correct primes here: 97, 31, 37.
*
Row 5: 14, 35, 93 ($3 \times 31$), 26, 68, 55, 78, 95, 24 are not prime. 19 is prime.
* Correct primes here: 19.
*
Row 6: 90, 6, 42, 98, 88 are not prime. 61(prime), 59(prime), 48, 79(prime), 7(prime).
* Correct primes here: 61, 59, 79, 7.
*
Row 7: 99, 33, 86, 69 ($3 \times 23$) are not prime. 41(prime), 25 ($5 \times 5$) is not prime. 60, 53(prime), 72, 82 are not prime.
* Correct primes here: 41, 53.
*
Row 8: 22, 49 ($7 \times 7$), 76, 39 ($3 \times 13$), 96 are not prime. 71(prime), 32, 66, 18, 52 are not prime.
* Correct primes here: 71.
*
Row 9: 81 ($9 \times 9$), 9, 54, 70, 91 ($7 \times 13$) are not prime. 73(prime), 17(prime), 83(prime), 67(prime), 44 are not prime.
* Correct primes here: 73, 17, 83, 67.
*
Row 10: 63, 46, 94, 15, 38, 87 ($3 \times 29$), 56, 20 are not prime. 11(prime), 100 are not prime.
* Correct primes here: 11.
Step 3: Compile the Final List
Based on the checks above, here are all the prime numbers found in the grid:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97.
There are 25 prime numbers between 1 and 100.
Final Answer:
The prime numbers to color are:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97
Parent Tip: Review the logic above to help your child master the concept of prime and composite numbers worksheet 5th grade.
