(a)[1]
State 6479 correct to the nearest 100.
(b)[1]
State the multiple of 13 that lies between 100 and 110.
(c)[1]
State the reciprocal of 0.6.
(d)[1]
Calculate $3 + 4 \times 2$.
(e)[1]
State an irrational number with a value between 15 and 20.
(f)[2]
By rounding each number in the expression to 1 significant figure, estimate the value of $\frac{423.8 - 78.4}{23.5}$. Show all your working.