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Learn how to write numbers in scientific notation using the power of ten, mantissa, and exponent. Practice problems included. Also covers multiplication, division, addition, and subtraction in scientific notation.
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SCIENTIFIC NOTATION FOR WRITING VERY BIG AND VERY SMALL NUMBERS
Easy to recognize because they are written as a power of ten • M X 108 EXPONENT + = large # - = small # MANTISSA: ONLY SIG FIGS.
TO WRITE A NUMBER IN SCIENTIFIC NOTATION • Find the sig. figs. • Move decimal between the 1st and 2nd sig. fig. → MANTISSA • # of spaces and direction moved → EXPONENT for the power of ten. left = positive right = negative
PROPER scientific notation form can only have ONE DIGITto the LEFT of the decimal
PRACTICE PROBLEMS • WRITE IN PROPER SCI. NOTATION FORM • 1) 405 000 000 000 mm • 2) 0.000 000 000 670 cg
ANSWERS • 1) 4.05 X 1011mm • 2) 6.70 X 10-10cg
MATH WITH SCI. NOTATION (and SIG FIGS) • MULTIPLICATION • MULTIPLY MANTISSAS • ADD EXPONENTS. • Ex.: (2.5 X 103 )(6.4 X 102) WORK: (2.5 * 6.4) X 103+2= 16 X 105 must correct for improper form • FINAL ANSWER: 1.6 X 106
Part of the work 2.5 X 6.4 100 150 16.00
DIVISION • DIVIDE MANTISSAS • SUBTRACT BOTTOM EXPONENT FROM TOP • Ex.: 4.5 X 1012 / 3 X 10-2 WORK: (4.5 / 3) X 1012–(-2)= 1.5 x 1014 • FINAL ANSWER: 2 x 1014
Part of the work 1.5 3 3 1 5 1 5 0 4.5
ADDITION • MUST HAVE SAME EXPONENT. ACHIEVED BY MOVING DECIMAL PT. IN THE MANTISSA • ADD MANTISSAS AND CARRY OVER EXPONENT.
Ex.: (1.5 X 103) + (3 X 102) = ? • WILL NOT MATTER WHICH EXPONENT YOU CHANGE; WILL CHANGE 2 TO A 3 • MOVE DECIMAL ONE PLACE TO LEFT (positive move) NOW NUMBER BECOMES .3 X 103 WORK:(1.5 X 103) + (.3 X 103) = 1.8 X 103 • FINAL ANSWER: 1.8 X 103
Part of the work • 1.5 • 0.3 • 1.8 X 103
SUBTRACTION • MUST HAVE SAME EXPONENT. ACHIEVED BY MOVING DECIMAL PT. IN THE MANTISSA • SUBTRACT MANTISSAS AND CARRY OVER EXPONENT.
Ex.: (2.1 X 10-3) – (5 X 10-2) = ? • WILL CHANGE –3 TO A –2 • MOVE DECIMAL TO LEFT ONE SPACE (positive move) NOW NUMBER BECOMES .21 X 10-2 WORK:(.21 X 10-2) – (5 X 10-2) = -4.79 X 10-2 • FINAL ANSWER: -5 X 10-2
Part of the work • 0.21 -5 • 5 OR 0.21 -4.79 X 10-2
PRACTICE PROBLEMS COPY AND WORK. ANSWERS MUST BE IN SCI. NOTATION WITH CORRECT SIG FIGS. • (6.78 x 1028) + (3.345 x 1027) =? • (4.3 x 10-12) – (7.89 x 10-11) =? • (2.75 x 1025)(3.3 x 10-34) =? 4) (7.20 x 108) / (1.2 x 10-12)=?
ANSWERS • 7.11 x 1028 • -7.46 x 10-11 • 9.1 x 10-9 4) 6.0 x 1020