Molar ratio - titrations

In the first equation, you use two moles of Cu(2+) to get one mole of I2. Then in the second equation, you react two moles of S2O3(2-) with that same one mole of I2 that formed.

Hence, in the overall reaction, the ratio Cu(2+) : I2 : S2O3(2-) is 2:1:2 so you can see that Cu(2+) and S2O3(2-) are in equimolar amounts. This is tricky to get your head around initially I admit!

Okayyy so since cu2+ and S2O3(2-) react in equal amounts its the same as a 1:1 ratio hence why it says 1 mol of cu2+ is equivalent to 1 mol of S2O3(2-) ?

I'm kind've starting to get it - I guess I just have to go over it again. Thank you