1/1×4+1/4×7+1/7×10+…+1/97×100
=3×(1/1×4+1/4×7+1/7×10+…+1/97×100)÷3
=(3/1*4+3/4*7+3/7*10+.+3/97*100)÷3
=(1-1/4+1/4-1/7+1/7-1/10+.-1/97+1/97-1/100)÷3
=(1-1/100)÷3
=99/100×1/3
=33/100
1/1×4+1/4×7+1/7×10+…+1/97×100
=3×(1/1×4+1/4×7+1/7×10+…+1/97×100)÷3
=(3/1*4+3/4*7+3/7*10+.+3/97*100)÷3
=(1-1/4+1/4-1/7+1/7-1/10+.-1/97+1/97-1/100)÷3
=(1-1/100)÷3
=99/100×1/3
=33/100