How do you plan to solve it?
To ensure there is a current of 10mA through the LED, the resistor must have a value of 5/0.01 = 500 Ohm
/*Paste your code here*/
#define led 2
void setup() {
pinMode(led, OUTPUT);
}
void loop() {
digitalWire(led, HIGH);
delay(400);
digitalWire(led, LOW);
delay(800);
}
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