# Subtraction of Units of Volume

## Students` Learning Outcomes

• Subtract measures of volume in same units with and without carrying.
• Solve real life problems involving same units of volume for subtraction with and without carrying.

### Information for Teachers

• Same units of measurement can be subtracted.

• We can subtract liters from liters and mL from Ml.

• Use vocabulary e.g. how many left? How many more?

• While teaching the lesson, the teacher should also consult textbook at all steps where and when applicable.

### Material / Resources

Writing board, chalk/marker, duster, pointer/stick, 50mL measuring cylinder, syringe of 5 mL beaker, textbook

### Introduction

• Tell a story to students:
• A shopkeeper had a drum of 200 liter oil. He sold 125 liter. How much is left?

### Development

Activity 1

• Describe a situation:
• If there are 150 mL of water is taken out from a 350 mL bottle. Find how much water is left in the bottle?
• Ask from students and solve above mentioned question on the board:

Activity 2

• Divide the class into two groups.
• Provide each group four 250 mL, one 1000 mL and two 500 mL, empty bottles.

• Ask the students to fill the one liter bottle first using 250 mL empty bottle and then using 500 mL bottle.

• How many 250 mL bottles can be filled with 1000 mL bottle? (Expected answer may be as; 4)
• How many 500 mL bottles can be filled with 1000 mL bottle? (Expected answer may be as; 2)
• How many 250 mL bottle can be filled with 500 mL bottle? (Expected answer may be as; 2)
• If we take out 250 mL from a 500 mL bottle then how much will left? (Expected answer may be as; 250 mL)

Activity 3

• In a village a water tank of capacity 10,000 liters is constructed. If in a day 200 liter is used then find there are how much water will left with?

### Sum up / Conclusion

• Smaller unit of measuring liquid is mL
• Subtraction is used to find the remaining liquid if some of it is used up.
• Only liter from liter and milliliter from milliliter is subtracted.

### Assessment

• Ask the students to find the difference between following quantities:

• Provide the students with 50 mL, measuring cylinder, and water in a beaker. Ask them to fill the cylinder with water up to the mark of 50mL. Now, ask them to suck the 5 mL water from the cylinder with the help of an injection syringe.
• Then ask from students :
• What is the volume of water remained there in the cylinder after using 5 mL from it?