12 multiple-choice questions, progressively harder.
Let a⋆b=2a+b−1a \star b = 2a + b - 1a⋆b=2a+b−1. What is 2⋆92 \star 92⋆9?
Solution
Correct answer: B
Substitute a=2a = 2a=2 and b=9b = 9b=9.
2⋆9=2(2)+9−1=4+9−1=122 \star 9 = 2(2) + 9 - 1 = 4 + 9 - 1 = 122⋆9=2(2)+9−1=4+9−1=12
Let a⋄b=a2−ba \diamond b = a^2 - ba⋄b=a2−b. What is 4⋄54 \diamond 54⋄5?
Correct answer: D
Square the first input, then subtract the second.
4⋄5=42−5=16−5=114 \diamond 5 = 4^2 - 5 = 16 - 5 = 114⋄5=42−5=16−5=11
Let a⋄b=a2−ba \diamond b = a^2 - ba⋄b=a2−b. What is 6⋄106 \diamond 106⋄10?
Correct answer: A
Square 666 first, then subtract 101010.
6⋄10=62−10=36−10=266 \diamond 10 = 6^2 - 10 = 36 - 10 = 266⋄10=62−10=36−10=26
Let a⋆b=2a+b−1a \star b = 2a + b - 1a⋆b=2a+b−1. What is (−3)⋆4(-3) \star 4(−3)⋆4?
Correct answer: C
The first input is negative, so 2a=2(−3)=−62a = 2(-3) = -62a=2(−3)=−6.
(−3)⋆4=2(−3)+4−1=−6+4−1=−3(-3) \star 4 = 2(-3) + 4 - 1 = -6 + 4 - 1 = -3(−3)⋆4=2(−3)+4−1=−6+4−1=−3
Let a⊕b=a+b+aba \oplus b = a + b + aba⊕b=a+b+ab. What is 2⊕52 \oplus 52⊕5?
Add the inputs, then add the product ababab.
2⊕5=2+5+(2)(5)=7+10=172 \oplus 5 = 2 + 5 + (2)(5) = 7 + 10 = 172⊕5=2+5+(2)(5)=7+10=17
Let a△b=3a−2ba \triangle b = 3a - 2ba△b=3a−2b. What is 5△15 \triangle 15△1?
Substitute a=5a = 5a=5 and b=1b = 1b=1.
5△1=3(5)−2(1)=15−2=135 \triangle 1 = 3(5) - 2(1) = 15 - 2 = 135△1=3(5)−2(1)=15−2=13
Let a⋆b=2a+b−1a \star b = 2a + b - 1a⋆b=2a+b−1. What is 0⋆60 \star 60⋆6?
With a=0a = 0a=0, the term 2a2a2a is 000.
0⋆6=2(0)+6−1=0+6−1=50 \star 6 = 2(0) + 6 - 1 = 0 + 6 - 1 = 50⋆6=2(0)+6−1=0+6−1=5
Let a⋄b=a2−ba \diamond b = a^2 - ba⋄b=a2−b. What is (−2)⋄5(-2) \diamond 5(−2)⋄5?
Squaring the negative input gives a positive, then subtract 555.
(−2)⋄5=(−2)2−5=4−5=−1(-2) \diamond 5 = (-2)^2 - 5 = 4 - 5 = -1(−2)⋄5=(−2)2−5=4−5=−1
Let a⊕b=a+b+aba \oplus b = a + b + aba⊕b=a+b+ab. What is 1⊕11 \oplus 11⊕1?
Both inputs are 111, so the product ababab is also 111.
1⊕1=1+1+(1)(1)=31 \oplus 1 = 1 + 1 + (1)(1) = 31⊕1=1+1+(1)(1)=3
Let a⋆b=2a+b−1a \star b = 2a + b - 1a⋆b=2a+b−1. What is 10⋆010 \star 010⋆0?
With b=0b = 0b=0, only 2a−12a - 12a−1 remains.
10⋆0=2(10)+0−1=20−1=1910 \star 0 = 2(10) + 0 - 1 = 20 - 1 = 1910⋆0=2(10)+0−1=20−1=19
Let a△b=3a−2ba \triangle b = 3a - 2ba△b=3a−2b. What is 6△66 \triangle 66△6?
Even with equal inputs the rule treats the slots differently.
6△6=3(6)−2(6)=18−12=66 \triangle 6 = 3(6) - 2(6) = 18 - 12 = 66△6=3(6)−2(6)=18−12=6
Let a⋄b=a2−ba \diamond b = a^2 - ba⋄b=a2−b. What is 7⋄97 \diamond 97⋄9?
7⋄9=72−9=49−9=407 \diamond 9 = 7^2 - 9 = 49 - 9 = 407⋄9=72−9=49−9=40
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