a, 4130 + 4130 + 4130 + 319 + 319 + 319
= 4130 × 3 + 319 × 3
= (4130 + 319) × 3
= 4449 × 3
= 13347
b, 1052 + 1052 – ( 286 + 286 + 286)
= 1052 × 2 – 286 × 3 = 2104 – 858
= 1246
c, 2020 + 2020 + 2010 + 2010 + 56 + 56
= 2020 × 2 + 2010 × 2 + 56 × 2
= (2020 + 2010 + 56) × 2
= 4086 × 2
= 8172
d, 2830 + 2830 + 2830 + 2830 +2830 = 2830 × 5 = 14150a