There are 10 word problems in each set. With my kids, I used them during maths rotations when their group was with me. This was our first try with written word problems, so we took turns picking a card, reading it and solving it together on white boards. Something about cards and getting to choose a 'mystery' one makes problem solving more fun! I've tried to keep the words relatively simple to read, and there are pictures to help with trickier words like caterpillar and watermelon.
These cards can be used in a variety of different ways, though. With kids who are confident readers and used to problem solving, I'd post the task cards around the room. Then I'd give each kid a clipboard and recording sheet (or just their maths journal) and have them find the problems and solve them (something about walking around the room makes problem solving more fun). These would also make great 'fast finisher' cards, or they could be used for 'math journaling' - where pupils are asked to take one card and solve it in their maths journals, showing both the abstract equation and a picture representation of the problem (so if they were adding 4 caterpillars and 3 bees to find out how many bugs, they would draw the correct number of caterpillars and bees, along with writing the mathematical equation 4 + 3 = 7). When we worked on these together in our maths groups, I put out some fun buggy counters to help the kids who are still needing lots of concrete practice in their problem solving.
I'd love to hear how you use (or plan to use) these cards in your own classroom!