The project The onebillion programme consists of two tablet apps, Maths 3-5 and Maths 4-6, that are designed to reinforce basic mathematical skills learned in the classroom. The apps are aimed at pupils aged 3-5 and 4-6 respectively and consist of mathematical activities organised around different topics such as counting, shape, and measures. Each topic is followed by an end-of-topic quiz which pupils are expected to pass before they move onto the next topic. The activities are aligned with the aims of the Early Years Foundation Stage and the National Curriculum in England. The apps were developed by onebillion, a not-for-profit organisation, and in this trial the delivery of the programme was led by a team from the University of Nottingham. This project tested the impact of onebillion when it is used by schools as a targeted intervention with small groups of pupils. The programme was targeted at Year 1 pupils (aged 5-6) who had been identified by their teachers as being in the lower half of the class in mathematics at the start of the school year. Pupils worked through the apps at their own pace and sessions were usually supervised by a teaching assistant (TA) or, in some cases, a teacher. The TAs' main tasks were to ensure that all the pupils had access to the onebillion apps throughout the session and to solve any technical problems. TAs were only occasionally expected to provide pedagogical support, for example if the pupil was struggling to progress past an end-of-topic quiz. The programme was designed to last for 12 weeks with four 30-minute sessions per week. The delivery team recommended to schools that the intervention is delivered outside of the time allocated to normal maths lessons. The Nottingham University team provided one half-day of face-to-face training, an Implementation Manual and instructional videos to support schools to use the apps. onebillion was evaluated using a two-arm randomised controlled trial (RCT): 113 schools were randomised to either receive the intervention or continue with business as usual teaching. The primary outcome was performance on a maths test (Progress Test in Maths [PTM], GL Assessment, 2015). A process evaluation involved interviews with TAs, observations of intervention sessions, and questionnaires given to TAs and other school staff. Recruitment for the trial started in September 2017 and the post-test took place in July 2018. Key conclusions 1. Pupils who received onebillion made an additional three months' progress in maths compared to the control group. This result has very high security. 88 onebillion Evaluation report Oxford University will create an identification number for each pupil and remove the names from the data files. To comply with the data protection act, the spreadsheet that connects the child's name and to the identification number will be saved in a separate password protected file.