Ella brought 7 new Christmas cards to add to her card collection this year. the next day she mailed half of her entire collection to her elf family and friends. there are now only 21 cards left. how many cards did Ella start with?

Respuesta :

Answer:

42

Step-by-step explanation:

the half of 42 is 21 so if she mailed the half of it then she just have 21 cards