5 + 5 is 10...
Start with 5 on one hand and use the other hand (count 5 on that one)
Word problem to make this a little bit 'simplier'
You have 5 squares (◾◾◾◾◾) and you tag along have more (◾◾◾◾◾). How many do you have all together? 10 squares.
◾◾◾◾◾ + ◾◾◾◾◾ (⬅count those squares )