Which digit in 1.896 has the least value?

'6' because it represents 'six thousandths'. ( 6/1000) or ( 0.006 )

In 1.896

The number column names are

'1' = units

Decimal point

'8' = tenths ( 8/10 = 0.8)

'9' = hundredthe ( 9/100 - 0.09)

'6' = thousandths ( 6/1000 = 0.006)