A. $3145 + 2496 + 5347 + 7504 + 4653$

 =$3145 + 2496 = 5641$
= $5641 + 5347 = 10988$
=$10988 + 7504 = 18492$
= $18492 + 4653 = 23145$

 B. $2376 + 3425 - 376 - 425$

= $2376 + 3425 = 4801$
= $4801 - 376 = 4425$
= $4425 - 425 = 4000$

 C. $3145 - 246 + 2347 - 145 + 4264 - 347$

= $3145 - 246 = 2899$
= $2899 + 2347 = 5246$
= $5246 - 145 = 5101$
=$5101 + 4264 = 9365$
= $9365 - 347 = 9018$

- A. $23145$
- B. $4000$
- C. $9018$

A=(2496+7504)+(5347+4653)+3145

   =10000+10000+3145

   =20000+3145

   =23145