Missing parts of ratios

This resource is designed for low ability year 7 and 8, but could be adapted for use in primary schools. Students are given a ratio and the amount in one part of the ratio and have to work out the size of the other part(s) of the ratio. The worksheet starts off using boxes and two part ratios allowing them to physically mark the parts into the boxes, then introduces three part ratios and no boxes enabling them to use any method they prefer. This worksheet is adapted from one by bballard (thank you) and is RAG differentiated.