OK, let's work through this together. We're starting with 157 and we're going to multiply it by 19, which means we add 157 to itself 19 times.
Step 1: 0 + 157 = 157
Step 2: 157 + 157 = 314
Step 3: 314 + 157 = 471
Step 4: 471 + 157 = 628
Step 5: 628 + 157 = 785
Step 6: 785 + 157 = 942
Step 7: 942 + 157 = 1099
Step 8: 1099 + 157 = 1256
Step 9: 1256 + 157 = 1413
Step 10: 1413 + 157 = 1570
Step 11: 1570 + 157 = 1727
Step 12: 1727 + 157 = 1884
Step 13: 1884 + 157 = 2041
Step 14: 2041 + 157 = 2198
Step 15: 2198 + 157 = 2355
Step 16: 2355 + 157 = 2512
Step 17: 2512 + 157 = 2669
Step 18: 2669 + 157 = 2826
Step 19: 2826 + 157 = 2983

So, 157*19 = 2983