The science behind
Friends For 10 & 20
A two-minute read for parents — what number bond training actually does for your child's maths, and why a game gets better results than a worksheet.
1 The core idea: number bonds
The single most important building block in early arithmetic is knowing number bonds — the pairs of numbers that add up to a target, like 3+7 or 4+6. Research in maths education consistently shows that children who have automatised these bonds perform significantly better in all later arithmetic: subtraction, multiplication, mental calculation and working with fractions.
Friends For 10 trains bonds to 10. Friends For 20 extends that to 20. These are exactly the two foundations that primary school curricula worldwide build on first.
2 Automaticity: faster than thinking
Understanding why 6+4=10 is important, but it is not enough on its own. The goal is automaticity — retrieving the answer so fast that it costs no mental effort at all.
Cognitive load theory (John Sweller) explains this precisely: reducing effort for low-level retrieval frees up capacity for higher-order thinking. Automatised bonds are essentially free — they cost nothing cognitively.
3 Why speed training is legitimate
Some parents worry that drilling for speed encourages shallow memorisation. The research tells a different story.
Speed and accuracy together are a reliable indicator of genuine automaticity, not just surface memorisation. A child who truly understands that 7+3=10 will also be fast. A child who is only guessing or counting on their fingers will be slow and inconsistent.
The game's 20-question format with a continuous timer creates exactly the right kind of pressure: meaningful enough to motivate, short enough to stay fun. The +15s penalty for a mistake teaches children that accuracy and speed are both part of the goal — which mirrors how these bonds need to work in real arithmetic.
4 Why a game beats a worksheet
The app responds within milliseconds. Research by John Hattie ranks immediate feedback among the highest-impact factors in learning. Waiting until a teacher marks a worksheet the next day is far less effective.
The leaderboard gives children a self-referenced goal — beating their own best time. Self-determination theory (Deci & Ryan) shows this kind of autonomous motivation produces deeper engagement and longer retention than external pressure.
The biggest driver of automaticity is repetition over time. Worksheets are done once and put away. A game that shows your name on a leaderboard gets played again. And again.
5 Short sessions, spaced over time
Cognitive science has known since Hermann Ebbinghaus in the 1880s that spaced practice — short sessions repeated over many days — produces dramatically stronger long-term retention than one long session.
Friends For 10 takes 30–90 seconds per round. That makes it ideal for daily micro-sessions: before school, after dinner, while waiting. A child who plays three rounds a day for three weeks will outperform a child who does a 45-minute worksheet session once a week, even if the total time is similar.
6 The step from 10 to 20
Friends For 10 lays the foundation. Once a child has automatised bonds to 10, Friends For 20 extends the same neural pattern to a larger number space — and actively teaches them to use bonds to 10 as building blocks.
7 What to expect over time
First sessions: Slow times and frequent mistakes are completely normal. The bonds are not yet automatised.
After 1–2 weeks: Noticeable drop in best times. The child starts recalling bonds rather than working them out.
After 3–4 weeks: Times stabilise at a personal best. At this point bonds are genuinely automatic.
Long term: Every arithmetic task that builds on these bonds — column addition, subtraction, multiplication, mental maths — becomes measurably easier.
A consistent finish under 20 seconds on Friends For 10, and under 35 seconds on Friends For 20, is a good signal that bonds are truly automatic.
These games do not replace good teaching — but they provide something a classroom cannot easily give: a motivating, repeatable, self-paced environment for the specific kind of practice that turns understanding into fluency.