Pick what you want, print the page. The answer key comes with it, on its own sheet, and it tells you the mistake behind every wrong choice — not just which letter is right.
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1.Ana adds up the first seven odd numbers: 1 + 3 + 5 + 7 + 9 + 11 + 13. Is her total odd or even, and what is it?[3]
Aodd, 47
Bodd, 49
Ceven, 48
Deven, 49
Eodd, 45
2.In the number 4073, what is the value of the digit 7?[3]
A3
B7
C70
D700
E4000
3.A tap drips about 3 times a minute. Roughly how many drips is that in one day?[3]
A180
B720
C1080
D4320
E43200
4.A jacket costs 80 pounds. In January the price rises by 20 percent. In February the new price falls by 20 percent. What is the price at the end of February?[3]
A80 pounds
B76.80 pounds
C64 pounds
D83.20 pounds
E96 pounds
5.What is the remainder when 7 to the power 100 is divided by 5?[3]
A1
B2
C3
D4
E0
6.What is the remainder when 2 to the power 30 is divided by 7?[4]
A1
B2
C4
D5
E6
7.Which of these numbers can be divided exactly by both 4 and 9?[4]
A96
B117
C132
D144
E153
8.A price goes up by 20%, then down by 20%. Compared with the original price, the final price is:[4]
A20% lower
B4% lower
Cthe same
D4% higher
E40% higher
9.What is the units digit of 7 multiplied by itself 2026 times, that is 7 to the power 2026?[5]
Ait cannot be found without a calculator
B1
C3
D7
E9
10.A and B are different digits. The two-digit number AB added to the two-digit number BA gives 132. What is A + B?[5]
A3
B6
C11
D12
E13
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Answer key — Math Kangaroo practice
Each wrong choice carries the thinking that produces it. When a student picks C, this is what they were doing.
1.B — odd, 49KA-0002Parity of numbers (odd/even behavior)
AI decided that adding odd numbers always keeps the total odd, and made an arithmetic slip as well.
CI paired the numbers up and forgot that with seven numbers one is left over, so I expected an even total.
DI added correctly but then labelled 49 as even because I had already decided the pairs would make it even.
EI added only the first six numbers and stopped before including the thirteen.
2.C — 70KA-0055Place value and digit positions
AI gave the last digit of the number instead of looking at the 7 at all.
BI gave the digit itself rather than what it is worth in the position it sits in.
DI counted the positions from the left, so I read the 7 as being in the hundreds place.
EI gave the value of the largest digit instead of the value of the 7.
3.D — 4320KA-0059Estimation and order of magnitude
AI worked out the drips in an hour and stopped there.
BI multiplied by the 24 hours but forgot the 60 minutes in each one.
CI used 6 hours in a day, thinking of waking hours rather than a whole day.
EI used 600 minutes in an hour rather than 60.
4.B — 76.80 poundsKA-0153Percentages and simple discounts
AI assumed a 20 percent rise and a 20 percent fall must cancel because the percentages match.
CI applied only the fall and forgot the rise.
DI got the size of the change right but the direction wrong.
EI applied only the rise and forgot the fall.
5.A — 1KA-0169Remainders and modular cycles
BI reduced 7 to 2 correctly but then used a remainder of 1 when dividing 100 by 4.
CI read the cycle backwards and landed on the entry before the right one.
DI used 100 divided by 4 giving 25 and read off the 25th entry as if the cycle had length 25.
EI assumed a power that large must be divisible by 5.
6.A — 1KA-0053Remainders and modular cycles
BI found the cycle 2, 4, 1 but read the remainder of 30 divided by 3 as one instead of zero.
CI counted the cycle positions from zero, which shifted my answer one step along.
DI divided 30 by 7 and used that remainder rather than the remainder of the powers.
EI assumed the remainder would be one less than the divisor because the power is large.