National Semiconductor Quiz Kid Racer educational calculator (COP420 instead of MM5799)

Chip labeled 
/035B
COP420-NPG/N

20 buttons: 0-9, +, -, x, /, Slow, Fast, Amateur, Pro, Complex, Tables
8 7-segment LEDs, 3rd from right is just =, 6th can display +-x/
1 green "right" LED

COP420 Pinout
1  GND    batt-
2  CKO    N/C
3  CKI    100pf cap to ground, 47K resistor to Vcc
4  /Reset cap to gnd, resistor to Vcc
5  L7     N/C
6  L6     LED segment G
7  L5     LED segment F
8  L4     LED segment E
9  IN1    keypad column 2
10 IN2    keypad column 3
11 Vcc    batt+ via switch
12 L3     LED segment D
13 L2     LED segment C
14 L1     LED segment B
15 L0     LED segment A
16 SI     batt -
17 SO     N/C
18 SK     green "right" LED
19 IN0    keypad column 1 (left)
20 IN3    keypad column 4
21 G0     digit 4 and keypad row 4
22 G1     digit 3 and keypad row 3
23 G2     digit 2 and keypad row 2
24 G3     digit 1 and keypad row 1 (bottom)
25 D3     digit 5 and keypad row 5
26 D2     digit 6
27 D1     digit 7
28 D0     digit 8


button matrix
           IN0            IN1             IN2            IN3
D3       AMATEUR          PRO           COMPLEX         TABLES
G0          7              8               9              /
G1          4              5               6              x
G2          1              2               3              -
G3        SLOW           FAST              0              +

LEDs
D0   D1   D2   D3   G0   G1  G2   G3

 -    -         -    -        -    -
| |  | |  \|/  | |  | |   -  | |  | |
 -    -    -    -    -        -    -
| |  | |  /|\  | |  | |   -  | |  | |
 -    -         -    -        -    -
 
 A    A         A    A       A    A
F B  F B  FAB  F B  F B  A  F B  F B
 G    G    E    G    G       G    G
E C  E C  CDG  E C  E C  G  E C  E C
 D    D         D    D       D    D