With Gupta advancements in mathmatics and astronomy, which of the following discoveries were most important to future generations? Mark all that apply.
1)Â Use of zero as a placeholderÂ
2)Â Numeric decimal systemÂ
3)Â Observing the earth to be round due to shadowsÂ
4) Concluding the earth spins on an axis 5) Use of coins as money