Devin tried to evaluate 7\times 5{,}0707×5,0707, times, 5, comma, 070 step by step.
\phantom{=}\greend7\times\blued{5{, }070}=7×5,070empty space, start color #1fab54, 7, end color #1fab54, times, start color #11accd, 5, comma, 070, end color #11accd
{\text{step } 1}step 1start text, s, t, e, p, space, end text, 1 =\greend7\times (\blued{5{,}000} + \blued{70} )=7×(5,000+70)equals, start color #1fab54, 7, end color #1fab54, times, left parenthesis, start color #11accd, 5, comma, 000, end color #11accd, plus, start color #11accd, 70, end color #11accd, right parenthesis
{\text{step } 2}step 2start text, s, t, e, p, space, end text, 2 =(\greend7 \times \blued{5{,}000}) + (\greend7 \times \blued{70})=(7×5,000)+(7×70)equals, left parenthesis, start color #1fab54, 7, end color #1fab54, times, start color #11accd, 5, comma, 000, end color #11accd, right parenthesis, plus, left parenthesis, start color #1fab54, 7, end color #1fab54, times, start color #11accd, 70, end color #11accd, right parenthesis
{\text{step } 3}step 3start text, s, t, e, p, space, end text, 3 =35{,}000 + 490=35,000+490equals, 35, comma, 000, plus, 490
{\text{step } 4}step 4start text, s, t, e, p, space, end text, 4 =39{,}900=39,900equals, 39, comma, 900
find devin's mistake.