Change the format of numbers

5

5

5 / 15

1/3

1234.

1234.

3 + 5I

3 + 5*I

2 / 3 + 5 / 7I

2/3 + (5*I)/7

1. + 5 / 7I

1. + 0.7142857142857143*I

N[Pi]

3.141592653589793

2.Pi

6.283185307179586

NumberForm[N[10Pi], 3]

NumberForm[31.41592653589793, 3]

NumberForm[N[Pi], {3, 10}]

NumberForm[3.141592653589793, {3, 10}]

AccountingForm[5.4]
AccountingForm[-5]
AccountingForm[10 ^ 12]

AccountingForm[1000000000000]

ScientificForm[1234567890000., 4]

ScientificForm[1.23456789*^12, 4]

EngineeringForm[N[E ^ 10], 5]

EngineeringForm[22026.465794806703, 5]

BaseForm[30, 2]

BaseForm[30, 2]

1 + NumberForm[2, 5]

1 + NumberForm[2, 5]