Salut!
a. 62 × 19 + 62 × 199 + 62 × 1999 =
62 × ( 19 + 199 + 1999 ) =
62 × 2217 =
137454
78 × 43 + 78 × 435 + 78 × 4035 =
78 × ( 43 + 435 + 4035 ) =
78 × 4513 =
352014
b. 86 × 496 + 86 × 354 - 86 × 529 =
86 × ( 496 + 354 - 529 ) =
86 × 321 =
27606
35 × 358 - 35 × 243 + 35 × 194 =
35 × ( 358 - 243 + 194 ) =
35 × 309 =
10815