Respuesta :

4 thousands = 4,000
21 tens = 21*10 = 210

210 + 4,000 = 4,210

Answer: 4,210
4 x 1 thousand  = 4000
21 x 1 ten = 210

 4000
+ 210
----------
 4210

Therefore, 4000 + 210 = 4210