Mia tried to multiply 90\times5090×5090, times, 50 by decomposing 909090 and 505050 into multiples of 101010. Her work is below: \begin{aligned} \phantom{=}&~90 \times50 =&~ (9\times 10) + (5\times10) &\greenD{\text{Step } 1} =&~ (9 \times 5) + (10\times10) &\goldD{\text{Step } 2} =&~45 + 100&\blueD{\text{Step } 3} =&~145&\purpleC{\text{Step } 4} \end{aligned}
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90×50
(9×10)+(5×10)
(9×5)+(10×10)
45+100
145
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Step 1
Step 2
Step 3
Step 4
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