



 
Hi Pat, The prefix milli comes from the Latin word mille, meaning one thousand. The prefix centi comes from the Latin centum, meaning hundred. Hence there are 1,000 millimeters in a meter and 100 centimeters in a meter. 1,000 is 10 times 100 and hence there are 10 millimeters in a centimeter. But $10 \times 6.7 = 67$ so 67 millimeters is 6.7 centimeters. I hope this helps,  


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