100以内所有奇数之和是:
1+3+5+…+99=100×25=2500,
7的倍数与11的倍数之和是:
7×(1+3+…+13)+11×(1+3+…+9)
=7×49+11×25,
=343+275,
=618,
7×11=77,
2500-618+77=1959,
答:在100以内与77互质的所有奇数之和是1959.
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