Worksheet generator

1.C — 30KA-0006Number lines and betweenness

• AI counted the tick marks and gave the position number instead of reading the value on the scale.
• BI worked out that each gap is worth 10 but then counted only as far as the tick before the arrow.
• DI counted the tick marks rather than the gaps between them, so every gap came out one step too small.
• EI counted the gaps from the right-hand end instead of from zero.

2.C — 6KA-0015Reading tables, charts, and graphs

• AI read the vertical scale as going up in ones instead of in twos.
• BI counted the gridlines between the two bar tops instead of reading the values off the scale.
• DI gave Mia's total instead of the difference between Mia and Leo.
• EI added the two amounts together rather than subtracting to find how many more.

3.C — 210KA-0057Clever regrouping (pair to round numbers)

• AI paired the numbers from the outside in but left the 20 out of every pair, so I added only up to 19.
• BI estimated the total as a round number instead of working it out.
• DI used eleven pairs of 20 instead of ten pairs of 21.
• EI multiplied 20 by 21 and forgot that pairing counts every number twice.

4.A — 12KA-0110Bar models for part–whole

• BI split the 48 into three parts instead of the four the bars actually make.
• CI halved the total, as if the two of them had the same number each.
• DI found Bo's share correctly but then gave Ana's number instead.
• EI gave Ana's total, which is three of the four boxes, rather than Bo's one.

5.A — 2 hoursKA-0162Rate, time, distance

• BI used only the slower car's speed and divided 300 by 90 the wrong way round.
• CI averaged the two speeds to 75 km/h and divided 300 by it, which ignores that both cars move at once.
• DI divided 300 by 60, using only the slower car.
• EI halved the distance to 150 and then divided by 150, applying the closing speed twice.

6.B — square 3KA-0005Nets and folding, 2D to 3D

• AI picked the square directly next to the shaded one in the net, but neighbours in the net share an edge on the cube.
• CI counted to the far end of the column, assuming the square furthest away in the net is the one opposite.
• DI picked one of the side flaps because it is not touching the shaded square in the drawing.
• EI picked the other side flap for the same reason, without tracking what happens as the net folds.

7.C — 16KA-0019Multi-step arithmetic word problems

• AI found what one child has left and gave that instead of the total for all four.
• BI divided 24 by 4 and then subtracted 2 twice, mixing up per-child steps with total steps.
• DI subtracted 2 pencils once from the whole pack instead of once from each of the four children.
• EI subtracted the 2 before sharing, so only one lot of 2 ever came out of the total.

8.D — 6KA-0085Line and rotational symmetry

• AI checked only the vertical and horizontal folds and stopped there.
• BI counted the lines through opposite corners and forgot the ones through opposite edges.
• CI assumed a hexagon behaves like a rectangle with a couple of extra folds.
• EI counted each line twice, once from each end.

9.B — 1KA-0089Building and counting with unit cubes

• AI assumed every small cube touches the outside somewhere.
• CI counted the cubes at the centre of each face, which are painted on one side.
• DI counted the corner cubes, which are the most painted rather than the least.
• EI gave the total number of small cubes instead of the unpainted ones.

10.C — 150KA-0117Rate, time, distance

• AI divided 150 by 60 and read the answer as minutes rather than hours.
• BI used 1.5 hours instead of 2.5, dividing 90 by 60 rather than 150.
• DI converted 2.5 hours as two hours and fifty minutes.
• EI multiplied the distance by 60 instead of dividing, then converted.

11.B — 9KA-0150Try small cases first

• AI counted one diagonal from each corner and stopped there.
• CI counted three diagonals from each corner but forgot that each one gets counted from both ends.
• DI counted every line joining two corners, including the six sides.
• EI multiplied six corners by three diagonals each and never halved.

12.A — 48 km/hKA-0174Rate, time, distance

• BI averaged the two speeds, which would only be right if equal TIME were spent at each, not equal distance.
• CI weighted the two speeds by their own values instead of by the time each leg took.
• DI halved the correct answer, dividing by the total distance twice.
• EI added the two speeds together, which gives a number faster than either leg and so cannot be an average of them.

13.B — 1KA-0017Truth-tellers and liars

• AI assumed everyone could be lying at once without checking that Cal's statement would then be true.
• CI found one consistent truth-teller and added another without testing whether both could hold together.
• DI assumed everyone was telling the truth without noticing that Ana's statement then contradicts Bo's.
• EI gave up after one assumption led to a contradiction, instead of trying the other assumption.

14.D — 19KA-0018Complementary counting

• AI counted the codes that avoid 3 entirely and gave that as my answer without subtracting.
• BI counted the codes with a 3 in the first position only and forgot the other two positions.
• CI counted the codes with exactly one 3 and forgot the ones with two or three of them.
• EI counted every possible code and forgot to remove the ones with no 3 at all.

15.A — blackKA-0043Invariants and monovariants

• BI noticed there are more white stones than black ones and guessed the majority colour would survive.
• CI tried a few orders, saw different-looking positions along the way, and assumed the ending must vary too.
• DI did not notice that every move takes two stones out and puts one back, so the count falls by exactly one each time.
• EI assumed the first move settles the outcome instead of looking for a quantity that no move can change.

16.D — 30KA-0047Counting by position (sliding window)

• AI counted only the sixteen smallest squares and stopped there.
• BI counted the small squares and the single big one, and forgot every size in between.
• CI counted the 2 by 2 squares as four rather than nine, splitting the board into blocks.
• EI used 4 by 4 positions for every size instead of shrinking the range as the square grows.

17.C — 55KA-0078Extremal / worst-case counting

• AI found the smallest possible total of the other nine and gave that instead of what is left.
• BI assumed the biggest number could be at most half the total.
• DI made the other nine numbers all equal to 1, forgetting that they have to be different from each other.
• EI ignored the other nine numbers entirely, as if the biggest could take the whole total.

18.C — 14KA-0139Dice and cube face relationships

• AI subtracted only the top face from 21, forgetting the hidden bottom face as well.
• BI guessed four middling numbers and added them without using the total of all six faces.
• DI subtracted only the bottom face of 4 from the total of 21.
• EI added the four largest numbers on the die rather than the four that are actually at the sides.

19.B — 7KA-0157The pigeonhole principle

• AI thought that one more than the number of colours must give three of a kind, which only guarantees a PAIR.
• CI got to two of each colour, then added one more for each colour instead of one more in total.
• DI assumed the worst case meant emptying the largest pile of 12 reds first.
• EI answered with the number of socks I want rather than the number I must take to be sure of them.

20.A — 2 hours 24 minutesKA-0159Combined work rates

• BI averaged the two times, but two taps together must be faster than either one alone.
• CI added the two times, which would be right for filling two tanks one after the other.
• DI halved the smaller of the two times, guessing that two taps must simply be twice as fast as one.
• EI found 2 hours 24 minutes correctly and then halved it a second time.