The number from 1 to 6 is equal to 100 with an operation symbol added in the middle

The number from 1 to 6 is equal to 100 with an operation symbol added in the middle

(4*5)*(6/3+2+1)=100

Add four symbols to make the formula equal to 51
1 2 3 4 5 6 7=51
2 3 4 5 6 7 1=51
3 4 5 6 7 1 2=51
5 6 7 1 2 3 4=51
6 7 1 2 3 4 5=51
7 1 2 3 4 5 6=51

1 + 2 - 3 + 4 + 5 + 6 * 7 = 51 2 - 3 + 4 + 5 + 6 * 7+1=513 + 4 + 5 + 6 * 7-1-2=514 + 5 + 6 * 7+1+2-3=515 + 6 * 7+1+2-3+4=516 * 7+1+2-3+4+5=51(7*1*2+3)*(4+5-6)=517*1+2+3*4+5*6=51

1234567, plus sign equals 51
There are five answers

(1/2+3)*4+5*6+7=51
-12-3+4-5+67=51
1+2+3-4+56-7=51
1+2-3+4+5+6*7=51
1*2+3*4+5*6+7=51
1+2*3+45+6-7=51
1+2*34-5-6-7=51
The following five questions meet the 4-year product requirements

Put the 8 numbers 12345678 in brackets and let them form exactly four formulas () + () = () + () = ()_ ( )_ () = filled in the first bracket

( 1)+( 6)=(7 )=(2 )+( 5)=(8 )_ (3 )_ (4) = filled in the first bracket