ABN Grid Method Sparks Outrage Among Spanish Parents

Grid Addition: The ABN Method That Angers Parents and Teachers

Why does a seven-year-old take longer to solve 36+45=81 than their parent can do it mentally? The answer lies in a three-by-three grid. This tool has infuriated many parents who sit down to help with homework and recognize nothing of what they see. According to forum reports, this is not an isolated incident at one school: a secondary teacher encountered it, including with a student from Galicia, while others claim the method originates from further abroad.

What Exactly Is Grid Addition

The procedure decomposes numbers before adding them, distributing the work across a matrix. As interpreted by one user, for 36+45, the number 36 is split into 30, 5, and 1: you add 45 to 30, then 5, then 1. However, 45 remains whole—no one touches it—which confuses observers looking over the notebook: if one number is decomposed, why not the other? One column of the grid, containing the 6 and the 1, is indecipherable without the teacher's instructions, a detail that triggers parental outrage.

The result is the same. The path triples the number of steps.

The Method Has a Name, Author, and Doctrine

It is called the ABN method, created and promoted by Jaime Martínez Montero, a teacher with degrees in Philosophy and Letters and Education Sciences, an education inspector, and a mathematics didactics expert. He has published over ten books and conducted various research projects on the subject. His principles include equality: there is no mathematical genius possessed by some students but not others, and society as a whole could achieve notable competence. On paper, it sounds reasonable. At the kitchen table, much less so.

Where It Comes From: US Common Core

Some place its origin across the Atlantic. The grid addition format is identified with methods taught in the United States under the Common Core standards, designed to help struggling learners manage without memorization. A cited example: converting 6+5 into 1+5+5, i.e., 1+10=11. Less memory, more decomposition. Critics warn that the consequence is teaching exceptions before rules.

Cases Where It Fails

Critics point out scenarios where the method fails. A secondary teacher found a second-year ESO (Compulsory Secondary Education) student using this approach; having studied in Galicia, the student took longer than peers and made mistakes half the time. The teacher eventually asked him to forget it. In another home, a girl struggles when adding three numbers with more than two digits. Those who have tried it on paper agree: it takes twice as long as traditional carrying, the familiar carry the one.

Who Defends the Grid

Not everyone sees it as an aberration. Some use mental grid addition instinctively, even before the method was named: 36+45 solves as 30+40+11, or 30+40+10+1. For simple calculations, they argue, it is faster than the classic algorithm and comes naturally with practice. The underlying debate differs: should children first memorize times tables and basic sums before learning shortcuts, or should shortcuts be the starting point? Critics are clear: you must learn to walk before you run, and in arithmetic, walking means memorizing.

Collateral Damage to Mental Calculation

Complaints extend beyond the classroom. Those who fail to internalize basic numbers suffer later: workers unable to adjust a linear sensor's offset or solve a rule of three mentally, and waitresses who cannot calculate coffee prices if the machine fails. The final domestic scene involves Lego exhibition entry fees: adults cost 2 euros, children 1 euro, and the ticket seller used a calculator to sum 2+1. The child stared in disbelief.

Given these points, logic suggests the grid should disappear from schools. Yet it remains, with its grids, indecipherable columns, and defenders. Meanwhile, the father next door solves 36+45 mentally and understands nothing.