1.

LDX #$01
STX $0200
LDY #$04
STY $0201

JSR ADD
STA $0210
JSR SUB
STA $0211

ADD:
CLC
LDA $0200
ADC $0201
RTS

SUB:
CLC
LDA $0200
SBC $0201
RTS
----------------------------------
2.

CLC
LDX #$00
LDY #$f0

FILL_20:
TYA
STA $20, X
PHA
INY
INX
CPX #$10
BNE FILL_20

LDY #$00

FILL_30:
PLA
TAX
STX $30, Y
DEX
INY
CPY #$10
BNE FILL_30