Each country has a important economical thing cover their money like gold for example.
If we have 1 tones of gold cover 1 million (of country money) means the weight of 1 money = 1 tones / 1 million .but if we print another millions it means the weight of 1 money becomes= 1 tones / 2 millions means the weight is decrease.
So any country try to balance between this two factor to make the local currency strong.