DeskMade

The classroom counting jar — 48 pieces of Halloween candy collected over two weeks by the whole class — has been emptied overnight. Whoever took it did not grab blindly. They added and subtracted carefully to take exactly the right amount. The addition sums on the evidence tally are not random. The subtraction working connects directly to the missing total. Someone who adds and subtracts fluently did this — and does it automatically, without effort. The Math Whodunnit: The Missing Candy Jar is C

The donation amount labels on the winter gift drive charity table have been mixed up. Every label showing tens and ones has been swapped with a different number — and each swap was chosen deliberately to look almost correct. Whoever rearranged them understood place value well enough to make every change plausible to a quick glance. They know what a tens digit means. They know how skip counting produces a sequence. They know expanded form well enough to reverse it convincingly. Five suspects. Fiv

The Grade 2 class survey — 78 students voted for their favourite school lunch over three weeks — has been altered. The chart on the display board now shows that pasta is unpopular and pizza is the runaway favourite. But the students remember voting very differently. The school principal is using the chart results to make a budget decision this Friday. Whoever changed the numbers understood exactly how tally charts, bar graphs, line plots, arrays, and even-and-odd groupings work. Every number was

The geometry display in the main corridor has been rearranged. Shape labels have been moved to the wrong shapes — each swap chosen to be as plausible as possible to a young student. The measurement poster shows every value shifted by exactly 2 centimetres. The clock display has the hour and minute hands drawn in reverse for each time shown. Grade 1 students copied the display into their homework books last Tuesday and got every answer wrong. Whoever rearranged the display understood shapes, meas

The classroom number wall was rearranged overnight. The tens and ones labels are on the wrong shelves. The skip-counting posters show incorrect sequences — correct for the first two terms, then deliberately wrong from the third. The expanded form display is reversed. Sixty-two Grade 1 and Grade 2 students use this wall every day, and their homework results confirm they copied down incorrect information. Whoever did this understood place value well enough to make every change look almost right. F

Forty crayons disappeared from the art room supply cabinet overnight — and the shelf counts were changed by precise amounts, not random ones. Whoever took them worked out exactly how many boxes to move from each colour group to make the shelves still look full. They added up totals. They subtracted what remained. They solved multi-step word problems to plan every step. Detective Chen has five suspects. The evidence is at five stations across the school. Your students are on the case. The Math Wh

Report card season is here. This free resource gives you 12 ready-to-use math comments across all four performance levels — Not Meeting, Approaching, Meeting, and Exceeding — plus a specific, copy-paste next step for each level. Every comment and every next step uses [Name] as a placeholder. Replace it with your student's name and paste directly into your report card system. No rewriting, no adapting — just copy and paste. The comments cover three core criteria from the full IB PYP math comment