Part 2/7:
The first step in solving any problem is thorough reading. It’s crucial to identify the relevant information that will help us formulate our strategy. From the problem, we gather that Eduardo has 83 marbles and Renato has 78. The key word here is "together,” which indicates that we will be adding these two quantities.
Next, we denote our strategy for solving this problem: we need to perform an addition since we are combining two quantities. Thus, we set up the equation:
83 (Eduardo’s marbles) + 78 (Renato’s marbles).
We break down the addition into units and tens:
3 units + 8 units equals 11. We write 1 (ten) down and carry over the 1.
8 tens (from 83) + 7 tens (from 78) + 1 (the carried-over value) gives us 16 tens.