Your students can practise estimating the answers to subtraction calculations using friendly numbers with these engaging code creator worksheets. A range of subtraction problems must be created for another classmate to estimate the answers. The classmate will round the first number in each calculation up or down to the nearest friendly ten. Some of the answers will be circled or highlighted. These numbers must describe the appearance of an emoji when used with the code provided. After solving the problems, the classmate must draw the correct emoji. Three differentiated versions of the worksheet are available. The first worksheet includes two-digit by one-digit calculations. The second worksheet has two-digit by two-digit calculations and requires more calculations than the first. The third version has three-digit by two-digit calculations and needs a word problem to be written. When you have decided which version of the worksheet to give to which students, you can print out the number of copies that you need and start the maths fun.