There are 20 whole numbers between 1 and 100 that use the digit 6 at least once.
Let's break this down:
We need to find all the numbers between 1 and 100 that contain the digit '6'. We can identify the numbers with '6' in the units place and the tens place.
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Numbers with 6 in the units place: 6, 16, 26, 36, 46, 56, 66, 76, 86, 96. This gives us 10 numbers.
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Numbers with 6 in the tens place: 60, 61, 62, 63, 64, 65, 66, 67, 68, 69. This gives us 10 numbers.
Notice that 66 appears in both lists. To avoid counting it twice, we need to subtract it once. Therefore, the total number of whole numbers between 1 and 100 using the digit 6 at least once is:
10 (units place) + 10 (tens place) - 1 (66 counted twice) = 19.
According to the reference, there are 20 "sixes" between 1 and 100. However, the question asks for how many numbers use the digit 6 at least once. The number 66 contains two "sixes", but represents only one number. Thus the reference statement that there are 20 sixes does not directly answer the question.
Let's explicitly list out the numbers containing the digit '6':
6, 16, 26, 36, 46, 56, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 76, 86, 96
Counting these gives us a total of 19 numbers.
