Решите устно. Вычисления начинайте выполнять с высших разрядов.

**Ответ:** 1) $4300 \cdot 20 = 86\,000$ $\begin{array}{c@{\quad}l} \times \begin{array}{r} 43 \\ 2 \end{array} & \begin{array}{l} 00 \\ 0 \end{array} \\ \hline \begin{array}{r} 86 \end{array} & \begin{array}{l} 000 \end{array} \end{array}$ 2) $3100 \cdot 30 = 93\,000$ $\begin{array}{c@{\quad}l} \times \begin{array}{r} 31 \\ 3 \end{array} & \begin{array}{l} 00 \\ 0 \end{array} \\ \hline \begin{array}{r} 93 \end{array} & \begin{array}{l} 000 \end{array} \end{array}$ 3) $2300 \cdot 40 = 92\,000$ $\begin{array}{c@{\quad}l} \times \begin{array}{r} 23 \\ 4 \end{array} & \begin{array}{l} 00 \\ 0 \end{array} \\ \hline \begin{array}{r} 92 \end{array} & \begin{array}{l} 000 \end{array} \end{array}$ 4) $3112 \cdot 30 = 93\,360$ $\begin{array}{c@{\quad}l} \times \begin{array}{r} 3112 \\ 3 \end{array} & \begin{array}{l} \phantom{0} \\ 0 \end{array} \\ \hline \begin{array}{r} 9336 \end{array} & \begin{array}{l} 0 \end{array} \end{array}$ 5) $4203 \cdot 20 = 84\,060$ $\begin{array}{c@{\quad}l} \times \begin{array}{r} 4203 \\ 2 \end{array} & \begin{array}{l} \phantom{0} \\ 0 \end{array} \\ \hline \begin{array}{r} 8406 \end{array} & \begin{array}{l} 0 \end{array} \end{array}$ 6) $1010 \cdot 50 = 50\,500$ $\begin{array}{c@{\quad}l} \times \begin{array}{r} 101 \\ 5 \end{array} & \begin{array}{l} 0 \\ 0 \end{array} \\ \hline \begin{array}{r} 505 \end{array} & \begin{array}{l} 00 \end{array} \end{array}$ 7) $23\,000 \cdot 30 = 690\,000$ $\begin{array}{c@{\quad}l} \times \begin{array}{r} 23 \\ 3 \end{array} & \begin{array}{l} 000 \\ 0 \end{array} \\ \hline \begin{array}{r} 69 \end{array} & \begin{array}{l} 0000 \end{array} \end{array}$ 8) $11\,000 \cdot 80 = 880\,000$ $\begin{array}{c@{\quad}l} \times \begin{array}{r} 11 \\ 8 \end{array} & \begin{array}{l} 000 \\ 0 \end{array} \\ \hline \begin{array}{r} 88 \end{array} & \begin{array}{l} 0000 \end{array} \end{array}$ 9) $42\,000 \cdot 20 = 840\,000$ $\begin{array}{c@{\quad}l} \times \begin{array}{r} 42 \\ 2 \end{array} & \begin{array}{l} 000 \\ 0 \end{array} \\ \hline \begin{array}{r} 84 \end{array} & \begin{array0000 \end{array} \end{array}$ 10) $40\,300 \cdot 20 = 806\,000$ $\begin{array}{c@{\quad}l} \times \begin{array}{r} 403 \\ 2 \end{array} & \begin{array}{l} 00 \\ 0 \end{array} \\ \hline \begin{array}{r} 806 \end{array} & \begin{array}{l} 000 \end{array} \end{array}$ 11) $12\,001 \cdot 40 = 480\,040$ $\begin{array}{c@{\quad}l} \times \begin{array}{r} 12001 \\ 4 \end{array} & \begin{array}{l} \phantom{0} \\ 0 \end{array} \\ \hline \begin{array}{r} 48004 \end{array} & \begin{array}{l} 0 \end{array} \end{array}$ 12) $23\,100 \cdot 30 = 693\,000$ $\begin{array}{c@{\quad}l} \times \begin{array}{r} 231 \\ 3 \end{array} & \begin{array}{l} 00 \\ 0 \end{array} \\ \hline \begin{array}{r} 693 \end{array} & \begin{array}{l} 000 \end{array} \end{array}$