109 8 7 6 5 4 3 21 = 1000 in "+, -, *, /, ()", pick out the appropriate symbols and fill in the numbers to make the formula true

109 8 7 6 5 4 3 21 = 1000 in "+, -, *, /, ()", pick out the appropriate symbols and fill in the numbers to make the formula true

10*(9-8+7-6)*5*(4+3+2+1)=1000;