OK, let's work through this together. We're starting with 48 and we're going to multiply it by 31, which means we add 48 to itself 31 times.
Step 1: 0 + 48 = 48
Step 2: 48 + 48 = 96
Step 3: 96 + 48 = 144
Step 4: 144 + 48 = 192
Step 5: 192 + 48 = 240
Step 6: 240 + 48 = 288
Step 7: 288 + 48 = 336
Step 8: 336 + 48 = 384
Step 9: 384 + 48 = 432
Step 10: 432 + 48 = 480
Step 11: 480 + 48 = 528
Step 12: 528 + 48 = 576
Step 13: 576 + 48 = 624
Step 14: 624 + 48 = 672
Step 15: 672 + 48 = 720
Step 16: 720 + 48 = 768
Step 17: 768 + 48 = 816
Step 18: 816 + 48 = 864
Step 19: 864 + 48 = 912
Step 20: 912 + 48 = 960
Step 21: 960 + 48 = 1008
Step 22: 1008 + 48 = 1056
Step 23: 1056 + 48 = 1104
Step 24: 1104 + 48 = 1152
Step 25: 1152 + 48 = 1200
Step 26: 1200 + 48 = 1248
Step 27: 1248 + 48 = 1296
Step 28: 1296 + 48 = 1344
Step 29: 1344 + 48 = 1392
Step 30: 1392 + 48 = 1440
Step 31: 1440 + 48 = 1488

So, 48*31 = 1488