I've been trying to wrap my mind around some of the Singapore math strategies. I was fortunate to receive a training 2 weeks ago about numbers sense and Singapore math strategies. A lot of what was talked about was building number sense and ability to play with numbers by students. I have noticed that when I ask students what makes ten, they are able to tell me, but they are unable to decompose and compose numbers.
To answer this gap in their learning I have created a few worksheets. These have number bonds and decomposing numbers for addition. I am working on 3.NBT.2 right now, and these are the first step towards getting them to add and subtract to the thousands place.
In addition to these pages, I also have these same pages but harder, as well as some addition pages with scaffolding for carrying.
Math Practice, Grade 3 (Singapore Math), Mental Math, Grade 3/Level 2: Strategies and Process Skills to Develop Mental Calculation (Singapore Math) and 70 Must-Know Word Problems, Grade 3 (Singapore Math) which were really helpful.
All of these sheets and more (13 worksheets!) are available on my TpT store.