Separate+Start+Unknown

Connie had some marbles. She gave 5 to Juan. Now she has 8 marbles left. How many marbles did Connie have to start with?
media type="file" key="Movie on 2010-09-21 at 14.04.mov" width="300" height="300" _-5=8


 * Strategy- Trial and Error**

We took a handful of units to represent "some". Then we gave 5 to Juan and moved the units away from the pile. We then counted out 8 for Connie and removed any excess units. Last, we joined the units from Juan and Connie to get 13.
 * Explanation of Strategy**

Start with "5" and count up eight 6 7 8 9 10 11 12 13 5+8=_
 * Counting Up To**

media type="file" key="counting.mov" width="300" height="300"

We put the number 5 in our head and counted up 8 times to arrive at the number 13.
 * Explanation of Strategy**

5+5=10 10+3=13
 * Facts**

media type="file" key="Facts.mov" width="300" height="300"

We started with 5 and joined it with 5 more from the 8. We then added the 3 left over to get to the answer 13.
 * Explanation of Strategy**