Question

How many whole numbers between 100 and 400 contain the digit 2?

Answer 1

lại là toán tiền anh

Answer 2

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Answer 3

200 - 299 = 100 numbers 

120 - 129 = 10 numbers and 320 - 329 = 10 numbers 

1x2 but *not* 122 (we already counted it) = 9 numbers 

3x2 but *not* 322 (already counted) = 9 numbers 

100 + 10 + 10 + 9 + 9 = 138 numbers

Answer 4

200 - 299 = 100 numbers 

120 - 129 = 10 numbers and 320 - 329 = 10 numbers 

1x2 but *not* 122 (we already counted it) = 9 numbers 

3x2 but *not* 322 (already counted) = 9 numbers 

100 + 10 + 10 + 9 + 9 = 138 numbers

Answer 5

200 - 299 = 100 numbers 

120 - 129 = 10 numbers and 320 - 329 = 10 numbers 

1x2 but *not* 122 (we already counted it) = 9 numbers 

3x2 but *not* 322 (already counted) = 9 numbers 

100 + 10 + 10 + 9 + 9 = 138 numbers

Answer 6

200 - 299 = 100 numbers 

120 - 129 = 10 numbers and 320 - 329 = 10 numbers 

1x2 but *not* 122 (we already counted it) = 9 numbers 

3x2 but *not* 322 (already counted) = 9 numbers 

100 + 10 + 10 + 9 + 9 = 138 numbers