All the maths worksheets for Year 1 are to be found by clicking on the Free Maths Worksheets link at the top of the page. The worksheets have been organised into categories following the guidelines of the primary Framework for Mathematics, although this is now under review.
The categories are:
Counting and Number: looking at counting small numbers in steps of one and writing numbers.
Know number facts: counting on and back in twos and knowing addition facts to 5.
Calculating: including adding small numbers, taking away and an introduction to money
Understanding shape: at this stage recognising triangles, rectangles and squares as well as introducing some 3D shapes
Measuring: using non standard measures and comparing
Handling Data: mainly making lists
Using and Applying Maths: making number stories and investigating.
Whilst there is a considerable amount here it is next to nothing compared to the URBrainy site which is the best that I have found online, with over 1700 colourful pages of maths for Year 1, including full answers.