Question

$(2.5 \times {10}^{ - 3} ) + (3 \times {10}^{ - 2} )$
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Answer 1

Make the same type of numbers together
2.5x3
10-3x10-2
2.5x3+10-3x10-2
2.5x3=7.5
10-3x10-2=10-5
7.5x10-5

=7.5x10-5
7.5x 10to the the power of -5