Those amounts are pre-printed on the Schedule SE based on the Internal Revenue code.
Line 7 on Schedule SE is $137,700 which is the maximum amount of earned income subject to Social Security tax.
Line 14 on Schedule SE is $5,640 which is the maximum amount for the Optional Method to figure net earnings from farm income.
IRS Schedule SE - https://www.irs.gov/pub/irs-pdf/f1040sse.pdf
