Page 89 - Mathematics GRADE 9, DE-STREAMED (MTH1W)
P. 89
▪ as illustrated in the chart below, when the size of an exponent decreases by 1, the value of the power is divided by the base, in this case, a:
Power
Expands to
Value
a^3
a x a xa
a^3
a^2
a xa
a^2
a^1
a
a
a^0
a/a
1
a^-1
1/a
1/a
a^-2
1/ a x a
1/a^2
• numbers expressed in scientific notation:
o a DNA strand has a width of about 2.5 × 10−9 m:
0.0000000025=2.5×1 ×1 ×1 ×1 ×1 ×1 ×1 ×1 ×1 10 10 10 10 10 10 10 10 10
= 2.5 × 10−9 m
o −4 000 000 000 = −4.0 × 10 × 10 × 10 × 10 × 10 × 10 × 10 × 10 × 10
= −4.0 × 109
• evaluating powers:
o powers expressed with rational number bases and integer exponents:
• −(24)=−(2×2×2×2) = −16
• (−4)4 =(−4)×(−4)×(−4)×(−4) = 256
• ( 13 ) 2 = 13 × 13 = 19
• 2 − 4 = ( 12 ) 4 =1
16
o powers expressed in formulas:
▪ when the length of one side of the base of a cube = 12.5 cm, then
volume of a cube = (side length)3 = (12.5 cm)3
= 12.5 cm × 12.5 cm × 12.5 cm = 1953.1 cm3
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