ProblemSum

Unlimited Singapore maths word problems, every one fully worked. Written for Primary 6 and the PSLE — and for any child of 10 to 13, anywhere. Ratio, fractions, percentage, algebra, average, rate, area and volume, and more. Not geometry figures, charts or patterns drawn as shapes — those are read off a picture, and this app writes questions. No account. No subscription. No internet connection. Pay once and it is yours. NOT A QUESTION BANK Most practice apps ship a fixed set of questions: work through them twice and your child is remembering answers instead of solving problems. ProblemSum has no such list. Every question is written when you ask for it, with its own names and numbers, and the working follows those numbers — so there is no end of the book to reach. ROOM TO WORK IT OUT A scratch pad sits beside the question on iPad and Mac, and on an iPhone turned on its side; held upright, it slides up from below. Draw the model with a finger or Apple Pencil, or type the sums. It never calculates: the PSLE's first paper allows no calculator. WORKED THROUGH, THE SINGAPORE WAY Tap Check Answer and the full solution opens, one tap from your own working. Most solutions begin by naming the strategy Singapore pupils are taught for that kind of problem — draw a model, before and after, work backwards, make a supposition, guess and check — then work every line, with a check at the end. Most questions also show a second way to solve it; the rest warn of the trap the question sets. WHY SINGAPORE MATHS In TIMSS, the international maths study, Singapore's 10-year-olds came first in 2015, 2019 and 2023. In the OECD's PISA, sat by 15-year-olds, it has finished first or second in maths in every round since 2009. Its methods — above all the bar model — are now taught in schools from England to the United States. OUTSIDE SINGAPORE The questions are set at the level of the PSLE, Singapore's end-of-primary exam. That suits strong 10- and 11-year-olds and most children of 12 and 13 — roughly Years 6 to 8 in the UK, or grades 5 to 7 in the US. Money is in dollars and cents, and every measure is metric. BAR MODELS, DRAWN PROPERLY Bars are drawn to scale with their units marked, the part that changes shaded, and brackets showing what is left. The rest is set out as it would be on paper: fractions stacked, ratios and money in their proper forms, and units carried through every line. WHAT IT COVERS, AND WHAT IT DOES NOT Everything is set at the level of today's PSLE, algebra included. Ratio runs deepest, then area and volume, fractions, whole numbers and percentage, then algebra, average and rate, then decimals and measurement — with money, age, time, discount and GST running through them. What it does not do: geometry from a figure, charts and graphs, and patterns drawn as shapes. Those are read off a diagram rather than a paragraph, so a word-problem generator cannot write them. The Info tab lists both sides of that line. ANSWER IT THE WAY YOU THINK OF IT $4.50 or 4.50. Three-quarters as 3/4 or 0.75. A time as 1.45 p.m. or 1345. 120 cm³ or just 120. A right answer is never marked wrong for its punctuation. COME BACK TO WHAT YOU HAVE DONE Recent questions stay on the device with your answers, marked right or wrong, your working and the full solution, and you can step through them one by one. ONE APP, EVERY LEARNER A profile for each child, each keeping its own score, so two children can share an iPad without sharing a total. IPHONE, IPAD AND MAC One purchase covers all three. The screen rearranges itself as it changes shape — an iPhone turned on its side, an iPhone Duo opened — and nothing written is lost. With a keyboard, Command-N gives the next question and Command-Return checks your answer. WORKS ANYWHERE, TELLS NO ONE ProblemSum makes no network connections at all. No analytics, no advertising, no data collection — everything is generated on the device and stays there. Spotted a mistake? Tell us at hello@problemsum.com.