Digits allowed: 0,2,3,4,6,7
Range: 2022≤N≤4482
To find: number of 4-digit numbers N
N is 4-digit⇒first digit =0
N≤4482⇒first digit∈{2,3,4}
Plan: split by the first digit
First digit∈{2,3,4}
Case d₁ = 3: 3abc
3000 ≤ 3abc ≤ 3777
count=63=216
Case d₁ = 2: 2abc ≥ 2022
⇒ abc ≥ 022
All 2abc = 6³ = 216
Exclude 2abc < 2022 ⇔ abc < 022
2000 to 2007:6 values
2020:1 value
total excluded=7
d1=2: 216−7=209
Case d₁ = 4: 4abc ≤ 4482
⇒ abc ≤ 482
a∈{0,2,3}: 3×62=108
a=4: 44bc≤4482 always⇒62=36
d1=4: 108+36=144
209+216+144=569
3×216=648
648−7−72=569
(7<2022, 72>4482)
569