Addition
B.1 Add numbers up to millions
B.2 Add numbers up to millions: word problems
B.3 Addition: fill in the missing digits
B.4 Properties of addition
B.5 Add 3 or more numbers up to millions
B.6 Addition patterns over increasing place values
B.7 Choose numbers with a particular sum
B.8 Estimate sums
B.9 Estimate sums: word problems