common anode 7 segment display trouble
You can just ground C and D to give a logic '0', otherwise TTL will behave as if the inputs are at logic '1'.

/LT and /RBI should be tied high, but TTL inputs are not supposed to be tied to Vcc, instead you can tie them to Vcc through a 1K resistor. Do the same with all inputs- either tie them to ground or to Vcc through 1K - do not leave inputs floating. Though it will appear to work if the inputs are supposed to be high, the noise immunity will be compromised without a pull-up. 

You can just use one of the anode connections, they are tied together internally.

You should have appropriate value resistors in series with each of the segment outputs, of course.