Question

How many numbers are equal to the sum of two odd, one digit numbers

Answer 1

The sum of any two odd, one-digit numbers will be an even number; only four such sums are one-digit numbers: 2, 4, 6, and 8, which means there are 4 numbers equal to the sum of two odd, one-digit numbers.

Step-by-step explanation:

The question asks how many numbers are equal to the sum of two odd, one-digit numbers. To answer this, we start by listing all possible odd, one-digit numbers: 1, 3, 5, 7, and 9. We then add each possible pair to find their sums. The possible sums of two odd, one-digit numbers are even, as adding two odd numbers always results in an even number. We are restricted to one-digit numbers for the sum, which limits our possible outcomes.

The one-digit even numbers are 2, 4, 6, and 8. These are the sums we can obtain by adding two odd, one-digit numbers together. Therefore, there are 4 numbers that satisfy the condition posed by the question. This can also be checked by actual addition:

• 1+1=2
• 1+3=4
• 1+5=6
• 1+7=8
• 3+3=6
• 3+5=8
• 5+5=10 (not a one-digit number)
• ... and so on, ensuring that all pairwise sums are considered.

Answer 2

Here is a list of the odd number paired

1+3, 1+5, !+7, and !+9 (there are 4 unique sums - 4, 6,8 and 10)
3+5, 3+7, 3+9 (notice I did not pair 3 with 1 and the the only new sum is 12)
5+7, 5+9 (the only new sum is 14)
7+9 (16 is a new sum)

The sums (no repeats) are 4,6,8,10,12,14 and 16 for a total of seven numbers.