IMC Key Stage 3 · 2. Digits and number construction
Write numbers by place value, read sums of powers of 2 in binary, follow digit sums through carries, and bound a number by its digit sum before using remainders mod 9.
IMC Key Stage 3 – Selected topics
Rewrite numbers given by digits (including reversals and 'number plus digits') by place value and solve the resulting digit equations.
Use binary writing to order and count numbers built from distinct powers of 2.
Predict how the digit sum changes when 1 is added, by counting carries.
Bound the number of digits of a number tied to its digit sum and finish with the rule $n\equiv S(n)\pmod 9$.