加總 二數 19位數 (11571)

C2{=SUM(LEFT(A2:B2,10)*1)+(LEN(SUM(RIGHT(A2:B2,9)*1))=10)&RIGHT(SUM(RIGHT(A2:B2,9)*1),9)

另解{=SUM(LEFT(A2:B2,10)*1)+LEFT(RIGHT((0&SUM(RIGHT(A2:B2,9)*1)),10))&RIGHT(SUM(RIGHT(A2:B2,9)*1),9)