Time to show your thinking! 1. Weigh 2 sea shells together. Write down the total weight in grams. _____grams (both shells) 2. Weigh only one of the sea shells. Write down the weight in grams. - _____grams (one shell) 3. Now subtract to find the weight of the other sea shell. = _____grams (other shell) 4. Now weigh the other shell. Were you correct? Why? 5. What did you learn about weight? 6. Why did we use the unit grams?