Twelve and fifty-four thousandths.
You write 54 thousandths in decimal form as: 0.054
2.112 = two and one hundred twelve thousandths.
12.905 is written as twelve and nine hundred five thousandths.
0.512 = five hundred twelve thousandths.
Seven and seven hundred twelve thousandths would be written as 7.712The "and" tells you where the decimal goes, "thousandths" tells you how many places there will be in the decimal part of your answer (3 decimal places for thousandths), and seven hundred twelve tells you how many thousandths there will be.
Seven thousandths in decimal form is 0.007
19 thousandths in decimal form is 0.019