`timescale 1ns/1ns module calculation( input clk, input rst_n, input [3:0] a, input [3:0] b, output [8:0] c ); wire [7:0] c1,c2; reg [7:0] c_r; mul4 inst0( .clk (clk ), .rst_n (rst_n ), .aa (a ), .bb (12 ), .cc (c1 ) ); mul4 inst1( .clk (clk ), .rst_n (rst_n...