 Hello and welcome to the session. In this session we will study various units of measure and method of conversion of units. Now units play a very important role in knowing measure of a quantity. In our daily life we often use units like his 5 feet tall, the table weighs 5 kilograms, a person walks 2 miles daily in the park. Here we see that kilograms, feet, miles are all units of measurement measuring weight, height and distance respectively. Thus different units are used to measure different quantities. Now there are two main systems for measuring. First is customary system and second is metric system. Now customary system is the US system of measurement and this system includes ages, feet, miles for distance and answers, pounds and terms for weight. And metric system is the international system for measurement and this system includes meter and kilometer for distance and grams and kilograms for weight. Now let us see conversion of units. Now suppose we are given that distance between two tons is 15,000 meters. Now here this distance seems to be very large although meter also measures distance but here it seems to be inappropriate. Here kilometer would have been more appropriate unit to measure distance. Now 50 kilometers is equal to 50,000 meters so we can convert 50,000 meters into 50 kilometers. So the distance between the two tons 50 kilometers which seems to be more appropriate thus we can convert the units according to the situation. Now let us see conversion of units of length. Now meter is the base unit for length in the metric system. From meter other units of length are devised to measure smaller and larger distance, millimeter, centimeter and kilometer are commonly used units for length. Now we have the following conversions for measuring length. Now here 1 centimeter is equal to 10 millimeters, 1 meter is equal to 100 centimeters, 1 kilometer is equal to 1000 meters. Now here you can see that millimeter is smallest unit of length so we have millimeter is less than centimeter is less than meter is less than kilometer. And now let us discuss conversion rules. Now let us see how to convert a unit to smaller unit. Now when we have to convert a unit to smaller unit we multiply. Now let us see an example for this. Here we want to convert 5 meters into centimeters. Now we know that meter is a larger unit and centimeter is a smaller unit and 1 meter is equal to 100 centimeters. So 5 meters is equal to, now here we multiply 5 with 100 centimeters and this is equal to 500 centimeters. Thus 5 meters is equal to 500 centimeters. Now let us see how to convert a unit to larger unit. Now when we have to convert a unit to larger unit then we divide. Now let us see an example for this. Here we have to convert 50,000 meters into kilometers. Now we know meter is a smaller unit and kilometer is a larger unit. Also 1 kilometer is equal to 1000 meters. So 1 meter will be equal to 1 upon 1000 kilometers. So 15,000 meters will be equal to 15,000 into 1 upon 1000 kilometers and this is equal to 50 kilometers. Now if we have to convert millimeter into kilometer then we first convert millimeter into centimeter and then centimeter into meter and then meter into kilometer. Now we know 10 millimeters is equal to 1 centimeter. So 1 millimeter is equal to 1 upon 10 centimeters. Thus 2 millimeters is equal to 2 into 1 upon 10 centimeters which is equal to 2 upon 10 centimeters. Now let us convert centimeters to meters. Now 2 upon 10 centimeters is equal to 2 upon 10 into 1 upon 100 meters which is equal to 2 upon 1000 meters. And now let us convert meters into kilometers. Now 2 upon 1000 meters is equal to 2 upon 1000 into 1 upon 1000 kilometers which is equal to 2 upon 1 million kilometers. And this is equal to 1 upon 500,000 kilometers. So we have learnt conversion of units for length. Similarly we can convert the units of time, weight and capacity. Now let us see the following table. And this table shows the relationship among the most commonly used customary and metric units of measure. First of all let us see units of length. Now in customary system we have 1 foot is equal to 12 inches, 1 yard is equal to 3 feet, 1 mile is equal to 5,200 and 80 feet and in metric system we have 1 meter is equal to 1000 millimeters, 1 meter is equal to 100 centimeters, 1 kilo meter is equal to 1000 meters. Now let us see units for weight that is units of measurement for weight. Now in customary system we have 1 pound is equal to 16 ounces, 1 ton is equal to 2000 pounds. And in metric system we have 1 gram is equal to 1000 milligrams and 1 kilogram is equal to 1000 grams. Now let us see units of measurement for capacity. Now in customary system we have 1 cup is equal to 8 fluid ounces, 1 pint is equal to 2 cups, 1 quash is equal to 2 pints and 1 gallon is equal to 4 quash. And in metric system we have 1 meter is equal to 1000 milliliters, 1 kilo meter is equal to 1000 liters and now let us see conversion of units for time. Now 1 minute is equal to 60 seconds, 1 hour is equal to 60 minutes, then 1 day is equal to 24 hours, 1 week is equal to 7 days and 1 year is equal to 365 days. And now let us discuss unit ratio. Now a unit ratio is a ratio in which denominator is 1 unit. For example we have 1 yard is equal to 3 feet which can be written as unit ratio 3 feet upon 1 yard. Similarly we have 1 kilometer is equal to 1000 meters so we can write it as unit ratio 1000 meters upon 1 kilometer. Similarly we can write each relationship in the above mentioned table as unit ratio. Now let us see conversion between the measurement system. Now above we have done customary and metric system of conversions separately. Now we can also convert customary unit to metric unit to customary unit. Now one of the important conversion is 1 inch is approximately equal to 2.54 centimeters where inch is customary unit and centimeter is metric unit. Now let us find that 9 centimeters is approximately equal to how many inches. Now we have 1 inch is approximately equal to 2.54 centimeters. So 1 centimeter is approximately equal to 1 upon 2.54 inches thus 9 centimeters is approximately equal to 9 into 1 upon 2.54 inches which is approximately equal to 9 upon 2.54 inches and this is approximately equal to 3.54 inches. So 9 centimeters is approximately equal to 3.54 inches. So in this session we have learnt units of measure and the method of conversion of units. And this completes our session. Hope you all have enjoyed this session.