Worksheet generator

1.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.

2.D — 16KA-0033Means, and working backwards from a mean

• AI subtracted the two means from each other and gave the difference as the removed number.
• BI assumed the removed number must be the new mean, since the mean dropped to 11.
• CI assumed removing a number equal to the old mean is what changes the mean.
• EI added the two totals instead of subtracting one from the other.

3.B — 15KA-0056Place value and digit positions

• AI checked that the digits differ and stopped, without working out how much the swap actually changes the number.
• CI saw a difference of 2 between the digits and expected that to give a change of 36.
• DI ignored the direction: swapping this number makes it smaller, not bigger.
• EI picked a number whose digits differ by 4 without noticing that the larger digit is already in front.

4.D — 2550KA-0058Clever regrouping (pair to round numbers)

• AI found the sum of 1 to 50 and forgot that every term here is twice as big.
• BI used 49 pairs instead of 25, losing one pair from the count.
• CI estimated the answer as a round number rather than pairing properly.
• EI paired the terms but forgot that pairing counts every number twice, so I never halved.

5.A — 1KA-0149Last-digit behavior of products and powers

• BI assumed every power of 3 ends in 3.
• CI found the cycle 3, 9, 7, 1 but counted its positions from zero, landing one step early.
• DI used a remainder of 2 instead of 0 when dividing 100 by the cycle length of 4.
• EI assumed a number this large has no reachable last digit, rather than looking for a repeat.